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201. According to Newton’s third law of motion, when two objects collide and exert equal and opposite forces on each other, which property remains conserved during the collision?
ⓐ. Kinetic energy
ⓑ. Potential energy
ⓒ. Angular momentum
ⓓ. Linear momentum
Correct Answer: Linear momentum
Explanation: According to Newton’s third law, when two objects collide, they exert equal and opposite forces on each other. The total linear momentum of the system (the two objects) remains conserved during the collision, provided no external forces act on the system.
202. In a closed system where no external forces are present, what happens to the total momentum before and after a collision between two objects?
ⓐ. Total momentum decreases after collision
ⓑ. Total momentum increases after collision
ⓒ. Total momentum remains constant
ⓓ. Total momentum becomes zero
Correct Answer: Total momentum remains constant
Explanation: In a closed system with no external forces, the total momentum before a collision between two objects is equal to the total momentum after the collision. This conservation of momentum is a direct consequence of Newton’s third law of motion.
203. A rocket accelerates upwards by ejecting exhaust gases downwards. According to Newton’s third law, how does the rocket’s momentum change during this process?
ⓐ. Momentum decreases
ⓑ. Momentum increases
ⓒ. Momentum remains constant
ⓓ. Momentum becomes zero
Correct Answer: Momentum remains constant
Explanation: According to Newton’s third law, when a rocket accelerates upwards by ejecting exhaust gases downwards, the momentum of the rocket-gas system remains constant. The momentum gained by the rocket upwards is equal to the momentum lost by the exhaust gases downwards.
204. During a collision between two billiard balls on a frictionless table, what remains constant throughout the collision process?
ⓐ. Speed of the balls
ⓑ. Acceleration of the balls
ⓒ. Force between the balls
ⓓ. Total momentum of the system
Correct Answer: Total momentum of the system
Explanation: In a collision between two billiard balls on a frictionless table, the total momentum of the system (both balls together) remains constant throughout the collision process. This conservation of momentum is a consequence of Newton’s third law.
205. When a person jumps off a stationary boat into the water, according to Newton’s third law, how does the boat react?
ⓐ. The boat moves backwards
ⓑ. The boat moves forwards
ⓒ. The boat remains stationary
ⓓ. The boat rotates
Correct Answer: The boat moves backwards
Explanation: According to Newton’s third law, when a person jumps off a stationary boat into the water, the boat reacts by moving backwards. This reaction occurs because the person exerts a force on the boat (pushing backwards) while jumping off, causing the boat to move in the opposite direction.
206. When a cannon fires a cannonball, according to Newton’s third law, how does the cannon recoil?
ⓐ. The cannon moves forward
ⓑ. The cannon moves backward
ⓒ. The cannon remains stationary
ⓓ. The cannon rotates
Correct Answer: The cannon moves backward
Explanation: According to Newton’s third law, when a cannon fires a cannonball, the cannon recoils backwards. This recoil happens because the cannonball exerts a force on the cannon (pushing it backwards) as it is ejected forward.
207. In a collision between a car and a truck, what determines the direction of their individual velocities after collision, according to Newton’s third law?
ⓐ. Their masses
ⓑ. Their initial velocities
ⓒ. The friction between them
ⓓ. The direction of impact
Correct Answer: The direction of impact
Explanation: According to Newton’s third law, in a collision between a car and a truck, the direction of their individual velocities after collision is determined by the direction of impact. The forces they exert on each other are equal and opposite, influencing their subsequent motions.
208. When a person walks on a moving boat from bow to stern, how does the boat react according to Newton’s third law?
ⓐ. The boat moves forward
ⓑ. The boat moves backward
ⓒ. The boat remains stationary
ⓓ. The boat rotates
Correct Answer: The boat rotates
Explanation: According to Newton’s third law, when a person walks on a moving boat from bow to stern (front to back), the boat reacts by rotating slightly in the opposite direction to the person’s movement. This rotation occurs because the person’s movement changes the distribution of mass on the boat, affecting its rotational inertia.
209. During a collision between two ice skaters on ice, what remains conserved according to Newton’s third law?
ⓐ. Temperature
ⓑ. Friction
ⓒ. Total momentum
ⓓ. Total energy
Correct Answer: Total momentum
Explanation: In a collision between two ice skaters on ice, according to Newton’s third law, the total momentum of the system (both skaters together) remains conserved. This means that the total momentum before the collision is equal to the total momentum after the collision, provided no external forces act on the system.
210. When a goalkeeper catches a fast-moving soccer ball, what happens to the goalkeeper and the ball according to Newton’s third law?
ⓐ. The goalkeeper moves backward
ⓑ. The goalkeeper moves forward
ⓒ. The goalkeeper remains stationary
ⓓ. The goalkeeper rotates
Correct Answer: The goalkeeper moves backward
Explanation: According to Newton’s third law, when a goalkeeper catches a fast-moving soccer ball, the goalkeeper moves backward. This backward motion is a reaction to the force exerted by the ball as it is caught, pushing the goalkeeper in the opposite direction.
211. What is momentum defined as in physics?
ⓐ. The force acting on an object
ⓑ. The resistance of an object to motion
ⓒ. The product of mass and velocity of an object
ⓓ. The acceleration of an object
Correct Answer: The product of mass and velocity of an object
Explanation: In physics, momentum is defined as the product of an object’s mass and its velocity. Mathematically, momentum (p) = mass (m) × velocity (v).
212. Which of the following quantities is momentum related to?
ⓐ. Weight
ⓑ. Density
ⓒ. Speed
ⓓ. Volume
Correct Answer: Speed
Explanation: Momentum is related to speed because it involves the velocity of an object. Momentum depends on both the mass and the velocity of the object.
213. If the mass of an object doubles and its velocity remains unchanged, how does its momentum change?
ⓐ. It doubles
ⓑ. It halves
ⓒ. It quadruples
ⓓ. It remains the same
Correct Answer: It doubles
Explanation: Momentum (p) = mass (m) × velocity (v). If mass doubles (2m) and velocity (v) remains unchanged, then momentum (p) = 2m × v, which means the momentum doubles.
214. When does an object have the greatest momentum?
ⓐ. When its velocity is zero
ⓑ. When its mass is zero
ⓒ. When both its mass and velocity are maximum
ⓓ. When both its mass and velocity are minimum
Correct Answer: When both its mass and velocity are maximum
Explanation: Momentum (p) = mass (m) × velocity (v). Momentum is greatest when both mass and velocity are at their maximum values.
215. What is the SI unit of momentum?
ⓐ. Kilogram-meter per second (kg·m/s)
ⓑ. Newton (N)
ⓒ. Joule (J)
ⓓ. Meter per second squared (m/s²)
Correct Answer: Kilogram-meter per second (kg·m/s)
Explanation: The SI unit of momentum is kilogram-meter per second (kg·m/s), which reflects the product of mass (in kilograms) and velocity (in meters per second).
216. If an object’s velocity is doubled and its mass remains unchanged, how does its momentum change?
ⓐ. It doubles
ⓑ. It halves
ⓒ. It quadruples
ⓓ. It remains the same
Correct Answer: It doubles
Explanation: Momentum (p) = mass (m) × velocity (v). If velocity doubles (2v) and mass (m) remains unchanged, then momentum (p) = m × 2v, which means the momentum doubles.
217. What property of an object does momentum depend on?
ⓐ. Weight
ⓑ. Volume
ⓒ. Speed
ⓓ. Charge
Correct Answer: Speed
Explanation: Momentum depends on the speed (velocity) of an object. It is a vector quantity that takes into account both the mass and the direction of the object’s motion.
218. Which of the following equations represents the correct relationship for momentum?
ⓐ. \( p = \frac{mv}{t} \)
ⓑ. \( p = \frac{mv}{2} \)
ⓒ. \( p = \frac{m}{v} \)
ⓓ. \( p = mv \)
Correct Answer: \( p = mv \)
Explanation: Momentum (p) is defined as the product of an object’s mass (m) and its velocity (v). Therefore, \( p = mv \) is the correct equation representing momentum.
219. In a collision between two objects, what remains conserved according to the principle of conservation of momentum?
ⓐ. Kinetic energy
ⓑ. Potential energy
ⓒ. Total momentum
ⓓ. Total mass
Correct Answer: Total momentum
Explanation: According to the principle of conservation of momentum, in a closed system with no external forces, the total momentum of the system remains constant before and after a collision between two objects.
220. If an object’s mass is tripled and its velocity is halved, how does its momentum change?
ⓐ. It triples
ⓑ. It doubles
ⓒ. It halves
ⓓ. It remains the same
Correct Answer: It triples
Explanation: Momentum (p) = mass (m) × velocity (v). If mass triples (3m) and velocity is halved (v/2), then momentum (p) = 3m × (v/2), which means the momentum triples.
221. What does the principle of conservation of linear momentum state?
ⓐ. The total momentum of a closed system remains constant if no external forces act on it.
ⓑ. Momentum can be created or destroyed in any interaction.
ⓒ. Momentum is directly proportional to the velocity of an object.
ⓓ. Momentum is inversely proportional to the mass of an object.
Correct Answer: The total momentum of a closed system remains constant if no external forces act on it.
Explanation: The principle of conservation of linear momentum states that the total momentum of a closed system remains constant if no external forces act on it. This principle is based on Newton’s third law of motion.
222. In which of the following scenarios is linear momentum conserved?
ⓐ. A ball rolling down a hill due to gravitational force
ⓑ. A rocket accelerating in space by expelling exhaust gases
ⓒ. A car braking to stop at a traffic signal
ⓓ. A swimmer diving into a pool
Correct Answer: A rocket accelerating in space by expelling exhaust gases
Explanation: Linear momentum is conserved when there are no external forces acting on a system. In the case of a rocket accelerating in space by expelling exhaust gases, the system (rocket + exhaust gases) is closed, and momentum is conserved.
223. If two ice skaters push against each other on a frictionless surface, what happens to their velocities?
ⓐ. They both come to a stop
ⓑ. They move in opposite directions
ⓒ. They move in the same direction
ⓓ. They exchange their positions
Correct Answer: They move in opposite directions
Explanation: According to conservation of linear momentum, when two ice skaters push against each other on a frictionless surface, they will move in opposite directions to conserve the total momentum of the system.
224. During a collision between two billiard balls on a table, what remains unchanged if no external forces are present?
ⓐ. Speed of the balls
ⓑ. Total energy of the balls
ⓒ. Total momentum of the balls
ⓓ. Acceleration of the balls
Correct Answer: Total momentum of the balls
Explanation: In a collision between two billiard balls on a table, if no external forces are present, the total momentum of the system (both balls together) remains unchanged due to conservation of momentum.
225. When a bullet is fired from a rifle, according to conservation of linear momentum, how does the rifle recoil?
ⓐ. The rifle moves forward
ⓑ. The rifle moves backward
ⓒ. The rifle remains stationary
ⓓ. The rifle rotates
Correct Answer: The rifle moves backward
Explanation: When a bullet is fired from a rifle, according to conservation of linear momentum, the rifle recoils backward. This recoil is a result of the bullet and the rifle exerting equal and opposite forces on each other due to Newton’s third law of motion.
226. If a ball collides with a wall and bounces back with the same speed, what can be said about the momentum exchange with the wall?
ⓐ. Momentum exchange is zero
ⓑ. Momentum exchange is positive
ⓒ. Momentum exchange is negative
ⓓ. Momentum exchange is conserved
Correct Answer: Momentum exchange is zero
Explanation: When a ball collides with a wall and bounces back with the same speed, the momentum exchange with the wall is zero. The ball changes direction, but the total momentum of the system (ball + wall) remains unchanged if no external forces act.
227. In a closed system where no external forces are present, what happens to the total momentum before and after a collision between two objects?
ⓐ. Total momentum decreases after collision
ⓑ. Total momentum increases after collision
ⓒ. Total momentum remains constant
ⓓ. Total momentum becomes zero
Correct Answer: Total momentum remains constant
Explanation: In a closed system with no external forces, the total momentum before a collision between two objects is equal to the total momentum after the collision. This conservation of momentum is a consequence of Newton’s third law of motion.
228. What principle governs the motion of objects in a collision scenario, ensuring that total momentum remains unchanged?
ⓐ. Principle of inertia
ⓑ. Principle of conservation of energy
ⓒ. Principle of conservation of momentum
ⓓ. Principle of action and reaction
Correct Answer: Principle of conservation of momentum
Explanation: The principle of conservation of momentum governs the motion of objects in a collision scenario, ensuring that the total momentum of a closed system remains unchanged if no external forces are present.
229. When a person jumps off a boat into the water, how does the boat react according to the principle of conservation of linear momentum?
ⓐ. The boat moves forward
ⓑ. The boat moves backward
ⓒ. The boat remains stationary
ⓓ. The boat rotates
Correct Answer: The boat moves backward
Explanation: According to the principle of conservation of linear momentum, when a person jumps off a boat into the water, the boat reacts by moving backward. This reaction occurs because the person and the boat exert equal and opposite forces on each other due to Newton’s third law.
230. During a collision between two cars, what remains conserved according to the principle of conservation of momentum?
ⓐ. Kinetic energy
ⓑ. Potential energy
ⓒ. Total momentum
ⓓ. Total mass
Correct Answer: Total momentum
Explanation: According to the principle of conservation of momentum, in a closed system with no external forces, the total momentum of the system remains constant before and after a collision between two objects.
231. What is impulse defined as in physics?
ⓐ. The force acting on an object
ⓑ. The resistance of an object to motion
ⓒ. The change in momentum of an object
ⓓ. The acceleration of an object
Correct Answer: The change in momentum of an object
Explanation: In physics, impulse is defined as the change in momentum of an object. It is equal to the force applied to the object multiplied by the time interval during which the force acts.
232. Which of the following equations represents the relationship between impulse and change in momentum?
ⓐ. \( I = \Delta v \)
ⓑ. \( I = F \times t \)
ⓒ. \( I = \frac{mv}{t} \)
ⓓ. \( I = \Delta p \)
Correct Answer: \( I = \Delta p \)
Explanation: Impulse (I) is equal to the change in momentum (\( \Delta p \)). Mathematically, \( I = F \times \Delta t = \Delta p \), where F is the force applied and \( \Delta t \) is the time interval over which the force acts.
233. If the force applied to an object is doubled, what happens to the impulse delivered to the object, assuming the time of impact remains unchanged?
ⓐ. It doubles
ⓑ. It halves
ⓒ. It quadruples
ⓓ. It remains the same
Correct Answer: It doubles
Explanation: Impulse (I) = Force (F) × Time interval (\( \Delta t \)). If the force (F) is doubled and the time interval (\( \Delta t \)) remains unchanged, then the impulse (I) delivered to the object doubles.
234. When catching a cricket ball, why do fielders pull their hands backward upon impact?
ⓐ. To increase the force of impact
ⓑ. To reduce the time of impact
ⓒ. To decrease the force of impact
ⓓ. To increase the time of impact
Correct Answer: To increase the time of impact
Explanation: Fielders pull their hands backward upon catching a cricket ball to increase the time of impact. Increasing the time of impact reduces the force applied to the hands, reducing the chance of injury due to high force.
235. If the time interval during which a force acts on an object is increased, what happens to the impulse delivered to the object, assuming the force remains unchanged?
ⓐ. It increases
ⓑ. It decreases
ⓒ. It remains the same
ⓓ. It becomes zero
Correct Answer: It increases
Explanation: Impulse (I) = Force (F) × Time interval (\( \Delta t \)). If the time interval (\( \Delta t \)) is increased and the force (F) remains unchanged, then the impulse (I) delivered to the object increases.
236. Which of the following is NOT a factor affecting the impulse delivered to an object?
ⓐ. Force applied
ⓑ. Time interval of force application
ⓒ. Mass of the object
ⓓ. Velocity of the object
Correct Answer: Velocity of the object
Explanation: The impulse delivered to an object depends on the force applied, the time interval of force application, and the mass of the object. Velocity affects momentum but is not a factor in determining impulse.
237. During a collision between two objects, why is it important to extend the time of impact?
ⓐ. To decrease the force of impact
ⓑ. To increase the force of impact
ⓒ. To decrease the impulse
ⓓ. To increase the momentum
Correct Answer: To decrease the force of impact
Explanation: Extending the time of impact during a collision reduces the force applied, which can minimize damage and injury. This concept is crucial in automotive safety design and sports equipment.
238. When a ball bounces off a wall, why does the ball experience a change in momentum?
ⓐ. Due to the gravitational force
ⓑ. Due to the normal force exerted by the wall
ⓒ. Due to the frictional force between the ball and the wall
ⓓ. Due to the impulse provided by the wall
Correct Answer: Due to the impulse provided by the wall
Explanation: When a ball bounces off a wall, the change in momentum of the ball is due to the impulse provided by the wall. The wall exerts a force on the ball over a short period, changing its velocity.
239. Which of the following is an example where impulse is crucial?
ⓐ. A stationary object on a table
ⓑ. A sprinter running at a constant speed
ⓒ. A car moving with constant velocity
ⓓ. A baseball bat hitting a ball
Correct Answer: A baseball bat hitting a ball
Explanation: In sports like baseball, the impact of a bat on a ball involves impulse. The force applied by the bat changes the ball’s momentum, determining its trajectory and distance.
240. In a collision between two cars, how does the impulse experienced by each car compare, assuming they experience the same force and time of impact?
ⓐ. Impulse is greater for the heavier car
ⓑ. Impulse is greater for the lighter car
ⓒ. Impulse is equal for both cars
ⓓ. Impulse cannot be determined
Correct Answer: Impulse is equal for both cars
Explanation: In a collision where both cars experience the same force and time of impact, the impulse experienced by each car is equal. This principle follows from the conservation of momentum and Newton’s third law.
241. In an elastic collision between two objects, which of the following quantities is conserved?
ⓐ. Kinetic energy
ⓑ. Potential energy
ⓒ. Total momentum
ⓓ. Total mass
Correct Answer: Total momentum
Explanation: In an elastic collision between two objects, total momentum is conserved. Both kinetic energy and momentum are conserved in an elastic collision, but momentum conservation is universal in all types of collisions.
242. During a head-on collision between two cars, which scenario indicates an inelastic collision?
ⓐ. Both cars bounce back after collision
ⓑ. Both cars stick together after collision
ⓒ. One car stops while the other moves on
ⓓ. One car moves faster after collision
Correct Answer: Both cars stick together after collision
Explanation: In an inelastic collision, the colliding objects stick together after collision, conserving momentum but not kinetic energy. This often results in deformation and loss of kinetic energy.
243. Why does a cannon recoil backward when it fires a cannonball?
ⓐ. Due to the force of gravity
ⓑ. Due to the explosion inside the cannon
ⓒ. Due to the conservation of momentum
ⓓ. Due to the conservation of energy
Correct Answer: Due to the conservation of momentum
Explanation: The cannon recoils backward when firing a cannonball due to the conservation of momentum. The cannonball gains forward momentum, causing the cannon to gain equal momentum in the opposite direction.
244. In a collision between a truck and a bicycle, which of the following statements is true about the total momentum before and after the collision?
ⓐ. Total momentum before equals total momentum after
ⓑ. Total momentum before is greater than total momentum after
ⓒ. Total momentum before is less than total momentum after
ⓓ. Total momentum before and after cannot be determined
Correct Answer: Total momentum before equals total momentum after
Explanation: In a collision between a truck and a bicycle, assuming no external forces act, total momentum before the collision equals total momentum after due to conservation of momentum.
245. When a spacecraft docks with the International Space Station (ISS), what principle ensures a safe approach and docking procedure?
ⓐ. Conservation of kinetic energy
ⓑ. Conservation of angular momentum
ⓒ. Conservation of linear momentum
ⓓ. Conservation of potential energy
Correct Answer: Conservation of linear momentum
Explanation: When a spacecraft docks with the ISS, conservation of linear momentum ensures a safe approach and docking procedure. Adjustments in momentum ensure both objects dock without collision.
246. Why is it essential for car manufacturers to consider the conservation of momentum in designing crumple zones?
ⓐ. To conserve kinetic energy during a collision
ⓑ. To reduce the impact force on passengers
ⓒ. To minimize the velocity of the vehicles
ⓓ. To increase the friction between colliding vehicles
Correct Answer: To reduce the impact force on passengers
Explanation: Car manufacturers design crumple zones to absorb kinetic energy during a collision, thus reducing the impact force on passengers. This approach helps improve vehicle safety.
247. In a billiard game, why does the cue ball slow down after colliding with another ball?
ⓐ. Due to friction between the balls
ⓑ. Due to the change in its shape
ⓒ. Due to the conservation of angular momentum
ⓓ. Due to the conservation of linear momentum
Correct Answer: Due to the conservation of linear momentum
Explanation: In a billiard game, the cue ball slows down after colliding with another ball due to the conservation of linear momentum. Some kinetic energy is also transferred, but momentum conservation governs the speed change.
248. When a rocket launches into space, why does it expel exhaust gases downward?
ⓐ. To increase the rocket’s velocity
ⓑ. To conserve angular momentum
ⓒ. To conserve linear momentum
ⓓ. To minimize air resistance
Correct Answer: To conserve linear momentum
Explanation: When a rocket launches into space, it expels exhaust gases downward to conserve linear momentum. The expelled gases provide an equal and opposite reaction force, propelling the rocket forward.
249. Why do astronauts wear thruster packs in space?
ⓐ. To increase their speed
ⓑ. To control their direction
ⓒ. To conserve potential energy
ⓓ. To conserve kinetic energy
Correct Answer: To control their direction
Explanation: Astronauts wear thruster packs in space to control their direction. By expelling gas in controlled bursts, they can change their orientation and make precise movements.
250. When a baseball player catches a ball, why does the player’s body move backward?
ⓐ. Due to conservation of kinetic energy
ⓑ. Due to conservation of linear momentum
ⓒ. Due to conservation of angular momentum
ⓓ. Due to conservation of potential energy
Correct Answer: Due to conservation of linear momentum
Explanation: When a baseball player catches a ball, the player’s body moves backward due to the conservation of linear momentum. The impact of catching the ball changes the player’s momentum, causing the backward movement.
251. In which of the following scenarios is an object in rotational equilibrium?
ⓐ. A wheel spinning at a constant speed
ⓑ. A ladder leaning against a wall
ⓒ. A child swinging on a swing
ⓓ. A seesaw with unequal weights
Correct Answer: A wheel spinning at a constant speed
Explanation: An object is in rotational equilibrium when its angular velocity is constant. A wheel spinning at a constant speed exhibits rotational equilibrium because there is no net torque acting on it.
252. For a body to be in translational equilibrium, which condition must be true?
ⓐ. The net force on the body must be zero
ⓑ. The net torque on the body must be zero
ⓒ. The body must be at rest
ⓓ. The body’s velocity must be constant
Correct Answer: The net force on the body must be zero
Explanation: Translational equilibrium requires that the vector sum of all forces acting on the body is zero. This condition ensures that the body’s acceleration is zero and its velocity remains constant.
253. Why does a tightrope walker carrying a balancing pole maintain equilibrium?
ⓐ. To reduce air resistance
ⓑ. To increase their speed
ⓒ. To lower their center of gravity
ⓓ. To control their rotational inertia
Correct Answer: To lower their center of gravity
Explanation: A tightrope walker carrying a balancing pole maintains equilibrium by lowering their center of gravity. This reduces the likelihood of tipping over and helps maintain balance on the tightrope.
254. In which situation is a body in stable equilibrium?
ⓐ. A ball balanced on top of a hill
ⓑ. A marble rolling in a straight line
ⓒ. A pencil standing on its tip
ⓓ. A book sliding on a table
Correct Answer: A ball balanced on top of a hill
Explanation: A body is in stable equilibrium when a small displacement from its equilibrium position results in a restoring force or torque that brings it back to equilibrium. A ball balanced on top of a hill is an example of stable equilibrium.
255. Which condition ensures rotational equilibrium for an object?
ⓐ. The sum of clockwise torques equals the sum of counterclockwise torques
ⓑ. The object is stationary
ⓒ. The net force acting on the object is zero
ⓓ. The object is accelerating
Correct Answer: The sum of clockwise torques equals the sum of counterclockwise torques
Explanation: Rotational equilibrium is achieved when the sum of all torques (moments) acting on an object is zero. This condition ensures that there is no net tendency for the object to rotate.
256. When a person sits on a chair without moving, what condition ensures the person is in equilibrium?
ⓐ. The person’s weight is balanced by the chair’s weight
ⓑ. The person’s muscles are relaxed
ⓒ. The person’s center of gravity is below the chair’s center of gravity
ⓓ. The normal force exerted by the chair equals the person’s weight
Correct Answer: The normal force exerted by the chair equals the person’s weight
Explanation: When a person sits on a chair without moving, equilibrium is maintained when the normal force exerted by the chair equals the person’s weight. This condition ensures the person does not accelerate vertically.
257. Why does a book lying on a table not fall through the table?
ⓐ. Due to the force of gravity
ⓑ. Due to the normal force exerted by the table
ⓒ. Due to the book’s weight
ⓓ. Due to the friction between the book and the table
Correct Answer: Due to the normal force exerted by the table
Explanation: A book lying on a table does not fall through because of the normal force exerted by the table. This force balances the gravitational force acting on the book, keeping it in equilibrium.
258. In which scenario is a body in unstable equilibrium?
ⓐ. A pencil standing on its tip
ⓑ. A satellite orbiting Earth
ⓒ. A rock on top of a hill
ⓓ. A toy car on a flat surface
Correct Answer: A pencil standing on its tip
Explanation: A body is in unstable equilibrium when any small displacement from its equilibrium position results in a net force or torque that further displaces it from equilibrium. A pencil standing on its tip is an example of unstable equilibrium.
259. When a person stands still on a scale, what does the scale measure?
ⓐ. The person’s weight
ⓑ. The person’s mass
ⓒ. The gravitational force on the person
ⓓ. The normal force exerted by the person
Correct Answer: The normal force exerted by the person
Explanation: When a person stands still on a scale, the scale measures the normal force exerted by the person on the scale, which is equal in magnitude to the person’s weight.
260. Why does a tightrope walker constantly adjust their position while walking?
ⓐ. To increase their speed
ⓑ. To lower their center of gravity
ⓒ. To increase air resistance
ⓓ. To conserve rotational inertia
Correct Answer: To lower their center of gravity
Explanation: A tightrope walker constantly adjusts their position while walking to lower their center of gravity. This adjustment helps maintain balance and reduces the risk of falling off the tightrope.
261. In which type of equilibrium do all forces and torques acting on an object balance each other at rest?
ⓐ. Static equilibrium
ⓑ. Dynamic equilibrium
ⓒ. Translational equilibrium
ⓓ. Rotational equilibrium
Correct Answer: Static equilibrium
Explanation: Static equilibrium occurs when all forces and torques acting on an object balance each other, resulting in no net force or torque and the object being at rest.
262. Which type of equilibrium describes a situation where all forces and torques acting on an object balance each other while the object moves at a constant velocity?
ⓐ. Static equilibrium
ⓑ. Dynamic equilibrium
ⓒ. Translational equilibrium
ⓓ. Rotational equilibrium
Correct Answer: Dynamic equilibrium
Explanation: Dynamic equilibrium describes a situation where all forces and torques acting on an object balance each other while the object moves at a constant velocity. This equilibrium can occur in systems with constant motion.
263. When a car travels at a constant speed along a straight road, what type of equilibrium does it maintain?
ⓐ. Static equilibrium
ⓑ. Dynamic equilibrium
ⓒ. Translational equilibrium
ⓓ. Rotational equilibrium
Correct Answer: Dynamic equilibrium
Explanation: A car traveling at a constant speed along a straight road maintains dynamic equilibrium. The forces (such as propulsion and air resistance) acting on the car are balanced, resulting in constant velocity.
264. What type of equilibrium exists when an object undergoes uniform circular motion?
ⓐ. Static equilibrium
ⓑ. Dynamic equilibrium
ⓒ. Translational equilibrium
ⓓ. Rotational equilibrium
Correct Answer: Dynamic equilibrium
Explanation: Uniform circular motion involves dynamic equilibrium where the object moves with constant speed along a circular path, and the centripetal force balances the outward centrifugal force.
265. Why does a cyclist coasting downhill at a constant speed experience dynamic equilibrium?
ⓐ. Due to gravity pulling the cyclist downward
ⓑ. Due to air resistance pushing against the cyclist
ⓒ. Due to the cyclist’s weight pushing downward
ⓓ. Due to the balance of all forces acting on the cyclist
Correct Answer: Due to the balance of all forces acting on the cyclist
Explanation: A cyclist coasting downhill at a constant speed experiences dynamic equilibrium because all forces acting on the cyclist (such as gravity and air resistance) are balanced, resulting in constant velocity.
266. Which type of equilibrium describes an object at rest on a horizontal surface with no external forces acting on it?
ⓐ. Static equilibrium
ⓑ. Dynamic equilibrium
ⓒ. Translational equilibrium
ⓓ. Rotational equilibrium
Correct Answer: Static equilibrium
Explanation: Static equilibrium describes an object at rest on a horizontal surface with no external forces acting on it. The object remains stationary because all forces and torques are balanced.
267. In a dynamic equilibrium situation, what happens if the forces acting on an object are not balanced?
ⓐ. The object moves with increasing velocity
ⓑ. The object accelerates in the direction of the unbalanced force
ⓒ. The object remains at rest
ⓓ. The object moves with constant velocity
Correct Answer: The object accelerates in the direction of the unbalanced force
Explanation: In dynamic equilibrium, if the forces acting on an object are not balanced, the object accelerates in the direction of the unbalanced force. Balanced forces are necessary to maintain constant velocity.
268. Why does a satellite orbiting Earth maintain dynamic equilibrium?
ⓐ. Due to the absence of gravity in space
ⓑ. Due to the balance of gravitational force and centripetal force
ⓒ. Due to the satellite’s constant speed
ⓓ. Due to the satellite’s weight
Correct Answer: Due to the balance of gravitational force and centripetal force
Explanation: A satellite orbiting Earth maintains dynamic equilibrium because the gravitational force pulling it toward Earth is balanced by the centripetal force required for circular motion. This balance results in constant velocity.
269. When a diver jumps off a diving board and reaches a constant falling speed, what type of equilibrium is demonstrated?
ⓐ. Static equilibrium
ⓑ. Dynamic equilibrium
ⓒ. Translational equilibrium
ⓓ. Rotational equilibrium
Correct Answer: Dynamic equilibrium
Explanation: When a diver jumps off a diving board and reaches a constant falling speed, it demonstrates dynamic equilibrium. The forces acting on the diver (gravity and air resistance) are balanced, resulting in constant velocity.
270. Why does a pendulum swinging back and forth demonstrate dynamic equilibrium?
ⓐ. Due to the pull of gravity
ⓑ. Due to air resistance
ⓒ. Due to the balance of forces at each point of swing
ⓓ. Due to the pendulum’s weight
Correct Answer: Due to the balance of forces at each point of swing
Explanation: A pendulum swinging back and forth demonstrates dynamic equilibrium because the tension and gravitational forces balance at each point of the swing, maintaining constant motion.
271. Why is it important for architects to consider equilibrium principles in building design?
ⓐ. To minimize construction costs
ⓑ. To ensure structural stability and safety
ⓒ. To maximize interior space
ⓓ. To enhance aesthetic appeal
Correct Answer: To ensure structural stability and safety
Explanation: Architects must consider equilibrium principles in building design to ensure structural stability and safety. Equilibrium ensures that the forces acting on a building are balanced, preventing structural failures.
272. How do engineers apply equilibrium principles in bridge design?
ⓐ. By maximizing traffic flow
ⓑ. By minimizing construction time
ⓒ. By ensuring weight distribution and load-bearing capacity
ⓓ. By reducing environmental impact
Correct Answer: By ensuring weight distribution and load-bearing capacity
Explanation: Engineers apply equilibrium principles in bridge design by ensuring weight distribution and load-bearing capacity. Equilibrium ensures that the forces exerted by the bridge’s structure and traffic are balanced to prevent collapse.
273. Why do civil engineers analyze the equilibrium of soil and foundations before constructing buildings?
ⓐ. To increase property value
ⓑ. To prevent soil erosion
ⓒ. To ensure stability and prevent settling
ⓓ. To facilitate landscaping
Correct Answer: To ensure stability and prevent settling
Explanation: Civil engineers analyze the equilibrium of soil and foundations before constructing buildings to ensure stability and prevent settling. Equilibrium analysis helps determine the appropriate foundation design to support the building’s weight.
274. In biomechanics, how are equilibrium principles applied to analyze human posture?
ⓐ. By enhancing athletic performance
ⓑ. By preventing injuries
ⓒ. By improving flexibility
ⓓ. By reducing fatigue
Correct Answer: By preventing injuries
Explanation: Equilibrium principles in biomechanics are applied to analyze human posture to prevent injuries. Understanding how forces act on the body helps biomechanists recommend ergonomic practices and correct posture to maintain equilibrium.
275. Why do ship designers use equilibrium principles in determining the ship’s stability?
ⓐ. To increase cargo capacity
ⓑ. To maximize speed
ⓒ. To prevent capsizing
ⓓ. To reduce fuel consumption
Correct Answer: To prevent capsizing
Explanation: Ship designers use equilibrium principles to determine the ship’s stability to prevent capsizing. Equilibrium analysis ensures that the ship’s center of gravity remains below the metacenter to maintain stability in various sea conditions.
276. How do biomechanical engineers use equilibrium principles to design prosthetic limbs?
ⓐ. By improving aesthetics
ⓑ. By maximizing comfort
ⓒ. By ensuring balance and stability
ⓓ. By reducing weight
Correct Answer: By ensuring balance and stability
Explanation: Biomechanical engineers use equilibrium principles to design prosthetic limbs by ensuring balance and stability. Equilibrium analysis helps optimize the limb’s weight distribution and joint mechanics for natural movement.
277. Why do architects consider the distribution of loads on skyscrapers when applying equilibrium principles?
ⓐ. To reduce construction costs
ⓑ. To enhance seismic resistance
ⓒ. To increase floor space
ⓓ. To improve energy efficiency
Correct Answer: To enhance seismic resistance
Explanation: Architects consider the distribution of loads on skyscrapers when applying equilibrium principles to enhance seismic resistance. Equilibrium ensures that the forces acting on the building are balanced, improving its ability to withstand earthquakes.
278. How do physicists use equilibrium principles in analyzing the stability of satellites in orbit?
ⓐ. By increasing satellite speed
ⓑ. By optimizing solar panel efficiency
ⓒ. By balancing gravitational and centripetal forces
ⓓ. By minimizing orbital decay
Correct Answer: By balancing gravitational and centripetal forces
Explanation: Physicists use equilibrium principles in analyzing the stability of satellites in orbit by balancing gravitational and centripetal forces. Equilibrium analysis ensures that the satellite maintains a stable orbit without drifting away or falling to Earth.
279. Why do mechanical engineers analyze equilibrium principles in designing suspension bridges?
ⓐ. To increase pedestrian access
ⓑ. To minimize construction materials
ⓒ. To ensure load distribution and structural integrity
ⓓ. To improve environmental sustainability
Correct Answer: To ensure load distribution and structural integrity
Explanation: Mechanical engineers analyze equilibrium principles in designing suspension bridges to ensure load distribution and structural integrity. Equilibrium analysis helps determine the tension in cables and the supporting structures needed to withstand loads.
280. How do architects apply equilibrium principles to design cantilever structures?
ⓐ. By maximizing sunlight exposure
ⓑ. By minimizing wind resistance
ⓒ. By balancing forces to prevent collapse
ⓓ. By reducing construction time
Correct Answer: By balancing forces to prevent collapse
Explanation: Architects apply equilibrium principles to design cantilever structures by balancing forces to prevent collapse. Equilibrium analysis helps determine the proper load distribution and support for the structure’s extended horizontal beam.
281. What is the formula to calculate the gravitational force between two objects?
ⓐ. \( F = \frac{G \cdot m_1 \cdot m_2}{d^2} \)
ⓑ. \( F = \frac{G \cdot m_1 \cdot m_2}{d} \)
ⓒ. \( F = G \cdot m_1 \cdot m_2 \cdot d \)
ⓓ. \( F = G \cdot \frac{m_1}{m_2} \cdot d^2 \)
Correct Answer: \( F = \frac{G \cdot m_1 \cdot m_2}{d^2} \)
Explanation: The gravitational force \( F \) between two objects of masses \( m_1 \) and \( m_2 \), separated by a distance \( d \), is given by \( F = \frac{G \cdot m_1 \cdot m_2}{d^2} \), where \( G \) is the gravitational constant.
282. What is the SI unit of gravitational constant \( G \)?
ⓐ. Newton
ⓑ. Joule
ⓒ. Pascal
ⓓ. \( \text{m}^3 \cdot \text{kg}^{-1} \cdot \text{s}^{-2} \)
Correct Answer: \( \text{m}^3 \cdot \text{kg}^{-1} \cdot \text{s}^{-2} \)
Explanation: The SI unit of the gravitational constant \( G \) is \( \text{m}^3 \cdot \text{kg}^{-1} \cdot \text{s}^{-2} \). It represents the strength of the gravitational interaction between two masses.
283. What happens to the gravitational force between two objects if the distance between them is doubled?
ⓐ. It increases by a factor of 2
ⓑ. It decreases by a factor of 2
ⓒ. It increases by a factor of 4
ⓓ. It decreases by a factor of 4
Correct Answer: It decreases by a factor of 4
Explanation: The gravitational force between two objects decreases by a factor of 4 if the distance between them is doubled, following the inverse-square law \( F \propto \frac{1}{d^2} \).
284. Which of the following pairs would experience the strongest gravitational force between them?
ⓐ. Two planets with masses \( 10^{23} \) kg and \( 10^{24} \) kg, separated by 1000 km
ⓑ. Two asteroids with masses \( 10^{18} \) kg and \( 10^{20} \) kg, separated by 1 million km
ⓒ. A star with mass \( 10^{30} \) kg and a planet with mass \( 10^{25} \) kg, separated by 100 million km
ⓓ. A satellite with mass \( 10^3 \) kg and a space station with mass \( 10^4 \) kg, separated by 500 km
Correct Answer: A star with mass \( 10^{30} \) kg and a planet with mass \( 10^{25} \) kg, separated by 100 million km
Explanation: The gravitational force is stronger between objects with larger masses and smaller distances. Hence, a star with a very large mass and a planet with a substantial mass, even if separated by a considerable distance, would experience the strongest gravitational force among the options given.
285. Why do astronauts experience weightlessness in space despite the presence of gravitational force?
ⓐ. Due to the absence of gravity in space
ⓑ. Due to the spacecraft’s speed
ⓒ. Due to the gravitational pull of other celestial bodies
ⓓ. Due to free-fall around Earth
Correct Answer: Due to free-fall around Earth
Explanation: Astronauts experience weightlessness in space due to free-fall around Earth. They and their spacecraft are falling towards Earth at the same rate, causing the sensation of weightlessness despite the presence of gravitational force.
286. Which scientist first formulated the law of universal gravitation?
ⓐ. Isaac Newton
ⓑ. Albert Einstein
ⓒ. Galileo Galilei
ⓓ. Johannes Kepler
Correct Answer: Isaac Newton
Explanation: Isaac Newton first formulated the law of universal gravitation, which states that every mass attracts every other mass in the universe with a force proportional to the product of their masses and inversely proportional to the square of the distance between them.
287. What happens to the gravitational force between two objects if their masses are doubled while keeping the distance between them constant?
ⓐ. It doubles
ⓑ. It quadruples
ⓒ. It remains the same
ⓓ. It halves
Correct Answer: It doubles
Explanation: According to Newton’s law of gravitation, if the masses of two objects are doubled while keeping the distance between them constant, the gravitational force between them doubles because the force is directly proportional to the product of the masses.
288. What is the approximate value of the gravitational constant \( G \)?
ⓐ. \( 6.674 \times 10^{-11} \, \text{Nm}^2/\text{kg}^2 \)
ⓑ. \( 9.81 \, \text{m/s}^2 \)
ⓒ. \( 3.00 \times 10^8 \, \text{m/s} \)
ⓓ. \( 1.67 \times 10^{-27} \, \text{kg} \)
Correct Answer: \( 6.674 \times 10^{-11} \, \text{Nm}^2/\text{kg}^2 \)
Explanation: The approximate value of the gravitational constant \( G \) is \( 6.674 \times 10^{-11} \, \text{Nm}^2/\text{kg}^2 \). It is a fundamental constant in physics used to calculate the gravitational force between masses.
289. What phenomenon occurs due to gravitational force that determines the orbits of planets around the Sun?
ⓐ. Tidal forces
ⓑ. Gravitational attraction
ⓒ. Magnetic repulsion
ⓓ. Electromagnetic induction
Correct Answer: Gravitational attraction
Explanation: Gravitational attraction is the phenomenon that determines the orbits of planets around the Sun. The Sun’s gravitational force keeps the planets in their elliptical paths around it.
290. Which factor does not affect the gravitational force between two objects?
ⓐ. Mass of the objects
ⓑ. Distance between the objects
ⓒ. Electric charge of the objects
ⓓ. Gravitational constant \( G \)
Correct Answer: Electric charge of the objects
Explanation: Gravitational force between two objects depends on their masses and the distance between them, according to Newton’s law of gravitation. Electric charge does not affect gravitational force.
291. What type of frictional force acts between two surfaces that are stationary relative to each other?
ⓐ. Static friction
ⓑ. Kinetic friction
ⓒ. Rolling friction
ⓓ. Fluid friction
Correct Answer: Static friction
Explanation: Static friction is the type of frictional force that acts between two surfaces that are stationary relative to each other. It prevents the surfaces from sliding past each other.
292. Which factor does not affect the magnitude of static friction between two surfaces?
ⓐ. Normal force
ⓑ. Surface roughness
ⓒ. Contact area
ⓓ. Relative velocity
Correct Answer: Relative velocity
Explanation: Static friction depends on the normal force (force pressing the surfaces together), surface roughness, and contact area. Relative velocity (speed at which the surfaces move relative to each other) does not affect static friction.
293. What happens to the static frictional force when an applied force tries to move an object but is less than the maximum static frictional force?
ⓐ. The object remains stationary
ⓑ. The object moves at constant speed
ⓒ. The object moves with increasing speed
ⓓ. The object moves with decreasing speed
Correct Answer: The object remains stationary
Explanation: If the applied force is less than the maximum static frictional force, the object remains stationary due to the static frictional force preventing it from moving.
294. What type of frictional force acts between two surfaces that are sliding past each other?
ⓐ. Static friction
ⓑ. Kinetic friction
ⓒ. Rolling friction
ⓓ. Fluid friction
Correct Answer: Kinetic friction
Explanation: Kinetic friction is the type of frictional force that acts between two surfaces that are sliding past each other. It opposes the motion of the surfaces.
295. Which statement best describes the relationship between kinetic frictional force and the normal force between two surfaces?
ⓐ. Kinetic frictional force is independent of the normal force
ⓑ. Kinetic frictional force is directly proportional to the normal force
ⓒ. Kinetic frictional force is inversely proportional to the normal force
ⓓ. Kinetic frictional force equals the normal force
Correct Answer: Kinetic frictional force is directly proportional to the normal force
Explanation: Kinetic frictional force is directly proportional to the normal force pressing the surfaces together. This relationship means that increasing the normal force increases the kinetic frictional force.
296. Which statement correctly compares the magnitudes of static frictional force and kinetic frictional force between two surfaces?
ⓐ. Static frictional force is greater than kinetic frictional force
ⓑ. Static frictional force is less than kinetic frictional force
ⓒ. Static frictional force equals kinetic frictional force
ⓓ. Static frictional force is independent of kinetic frictional force
Correct Answer: Static frictional force is greater than kinetic frictional force
Explanation: Static frictional force can be greater than kinetic frictional force. The maximum static frictional force is greater than the kinetic frictional force between the same two surfaces.
297. Why is kinetic frictional force sometimes referred to as sliding friction?
ⓐ. Because it occurs only during sliding motion
ⓑ. Because it prevents sliding motion
ⓒ. Because it depends on surface roughness
ⓓ. Because it is independent of surface area
Correct Answer: Because it occurs only during sliding motion
Explanation: Kinetic frictional force is sometimes referred to as sliding friction because it acts only when surfaces are sliding past each other, opposing the relative motion between them.
298. Which factor affects the magnitude of kinetic frictional force between two surfaces?
ⓐ. Surface area
ⓑ. Normal force
ⓒ. Surface roughness
ⓓ. Both B and C
Correct Answer: Both B and C
Explanation: The magnitude of kinetic frictional force depends on both the normal force (force pressing the surfaces together) and surface roughness. It is independent of surface area.
299. In which scenario would rolling friction typically be encountered?
ⓐ. A sled sliding down a hill
ⓑ. A car accelerating on a highway
ⓒ. A bicycle moving on a road
ⓓ. A ball rolling across a floor
Correct Answer: A ball rolling across a floor
Explanation: Rolling friction is encountered when a round object (like a ball or wheel) rolls across a surface. It is typically less than sliding or kinetic friction.
300. How does fluid friction differ from other types of frictional forces?
ⓐ. It occurs between solid surfaces
ⓑ. It depends on the viscosity of the fluid
ⓒ. It is not affected by the shape of objects
ⓓ. It is independent of the relative velocity
Correct Answer: It depends on the viscosity of the fluid
Explanation: Fluid friction (also called drag) occurs between an object and a fluid (liquid or gas). It depends on the viscosity of the fluid, the shape of the object, and the relative velocity between the object and the fluid.
This section features Class 11 Physics MCQs – Chapter 5: Laws of Motion (Part 3). The entire series consists of 490 multiple-choice questions with correct answers and explanations, divided into 5 parts for easy practice. Based on the NCERT syllabus, these questions are extremely important for scoring well in board exams and excelling in competitive exams like JEE, NEET, and other state-level entrance tests. In this part, you will attempt another 100 MCQs with solutions covering advanced force problems, motion on inclined planes, and conceptual case studies.
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