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201. A 2 kg box is pushed horizontally across a frictionless surface with a constant force of 5 N for a distance of 10 m. Calculate the work done on the box.
ⓐ. 5 J
ⓑ. 10 J
ⓒ. 15 J
ⓓ. 20 J
Correct Answer: 20 J
Explanation: Work done \( W = F \cdot d = 5 \times 10 = 50 \) J. Since the force is constant and in the direction of motion, the work done is 20 J.
202. How can the Work-Energy Theorem be applied to calculate the speed of an object after it has been acted upon by a constant force over a certain distance?
ⓐ. By finding the object’s acceleration
ⓑ. By calculating the change in kinetic energy
ⓒ. By measuring the object’s potential energy
ⓓ. By analyzing the force of friction
Correct Answer: By calculating the change in kinetic energy
Explanation: According to the Work-Energy Theorem, the work done by the net force on an object equals the change in its kinetic energy. This change in kinetic energy can be used to determine the object’s final speed.
203. A spring with a spring constant of 200 N/m is compressed by 0.2 m. Calculate the potential energy stored in the spring.
ⓐ. 2 J
ⓑ. 4 J
ⓒ. 8 J
ⓓ. 16 J
Correct Answer: 2 J
Explanation: Potential energy stored in a spring \( PE = \frac{1}{2} k x^2 \), where \( k \) is the spring constant and \( x \) is the compression. \( PE = \frac{1}{2} \times 200 \times (0.2)^2 = 2 \) J.
204. How does the Work-Energy Theorem explain the motion of a rocket in space?
ⓐ. By calculating its gravitational potential energy
ⓑ. By determining its initial speed
ⓒ. By analyzing the work done by its engines
ⓓ. By measuring its acceleration
Correct Answer: By analyzing the work done by its engines
Explanation: The Work-Energy Theorem relates the work done by all forces on an object to its change in kinetic energy. In the case of a rocket, the engines do work to accelerate the rocket, thereby changing its kinetic energy and affecting its motion.
205. A skier slides down a hill and reaches the bottom with a certain speed. How does the Work-Energy Theorem relate to the skier’s motion?
ⓐ. By calculating the gravitational force
ⓑ. By analyzing changes in momentum
ⓒ. By relating work to changes in kinetic energy
ⓓ. By measuring the frictional force
Correct Answer: By relating work to changes in kinetic energy
Explanation: The Work-Energy Theorem directly relates the work done by all forces acting on the skier (like gravity and friction) to changes in the skier’s kinetic energy as they slide down the hill.
206. Why is the concept of potential energy essential when using the Work-Energy Theorem?
ⓐ. It helps calculate the object’s acceleration
ⓑ. It accounts for the effects of air resistance
ⓒ. It explains the forces acting on the object
ⓓ. It quantifies stored energy due to position
Correct Answer: It quantifies stored energy due to position
Explanation: Potential energy, whether gravitational, elastic (like in a spring), or electrical, represents stored energy due to an object’s position or configuration. This energy is crucial in the application of the Work-Energy Theorem.
207. A car accelerates from rest to 25 m/s in 10 seconds. How can the Work-Energy Theorem be applied to analyze this acceleration?
ⓐ. By calculating the car’s fuel efficiency
ⓑ. By measuring the engine’s power output
ⓒ. By determining the total force acting on the car
ⓓ. By relating the work done to the change in kinetic energy
Correct Answer: By relating the work done to the change in kinetic energy
Explanation: According to the Work-Energy Theorem, the work done by the net force on the car equals the change in its kinetic energy. This relationship helps analyze the car’s acceleration over time.
208. What does the Work-Energy Theorem state about the total work done on an object in any given situation?
ⓐ. It equals the force applied
ⓑ. It equals the power generated
ⓒ. It equals the change in momentum
ⓓ. It equals the change in kinetic energy
Correct Answer: It equals the change in kinetic energy
Explanation: The Work-Energy Theorem states that the net work done on an object by all forces equals its change in kinetic energy, whether increasing or decreasing.
209. In which scenario would the Work-Energy Theorem be most applicable for calculating the energy changes of a system?
ⓐ. A free-falling object
ⓑ. A stationary object
ⓒ. An object moving at constant speed
ⓓ. An object under constant acceleration
Correct Answer: A free-falling object
Explanation: For a free-falling object, gravity does work on it, changing its kinetic energy according to the Work-Energy Theorem.
210. How does the Work-Energy Theorem differ from the Work-Power Theorem in its application?
ⓐ. It calculates potential energy
ⓑ. It focuses on changes in kinetic energy
ⓒ. It measures the effects of friction
ⓓ. It relates to electrical energy
Correct Answer: It focuses on changes in kinetic energy
Explanation: The Work-Energy Theorem specifically relates the net work done on an object to changes in its kinetic energy, providing a direct relationship between work and energy changes.
211. What is the definition of power in physics?
ⓐ. The rate of doing work
ⓑ. The force applied to an object
ⓒ. The displacement of an object
ⓓ. The resistance in a circuit
Correct Answer: The rate of doing work
Explanation: Power is defined as the rate at which work is done or the rate at which energy is transferred or converted.
212. How is power calculated when work \( W \) is done over time \( t \)?
ⓐ. \( P = \frac{W}{t} \)
ⓑ. \( P = W \times t \)
ⓒ. \( P = \frac{t}{W} \)
ⓓ. \( P = W – t \)
Correct Answer: \( P = \frac{W}{t} \)
Explanation: Power \( P \) is calculated as the work \( W \) done divided by the time \( t \) taken to do that work.
213. A motor does 5000 J of work in 10 seconds. What is its power output?
ⓐ. 500 W
ⓑ. 1000 W
ⓒ. 2500 W
ⓓ. 5000 W
Correct Answer: 1000 W
Explanation: \( P = \frac{W}{t} = \frac{5000 \text{ J}}{10 \text{ s}} = 1000 \text{ W} \).
214. Which SI unit is used to measure power?
ⓐ. Joule
ⓑ. Watt
ⓒ. Newton
ⓓ. Pascal
Correct Answer: Watt
Explanation: The SI unit of power is the watt (W), named after James Watt, which is equivalent to one joule per second.
215. A cyclist exerts a force of 200 N to maintain a speed of 5 m/s. What is the power output of the cyclist?
ⓐ. 100 W
ⓑ. 200 W
ⓒ. 400 W
ⓓ. 1000 W
Correct Answer: 1000 W
Explanation: Power \( P \) can be calculated using \( P = F \times v \), where \( F \) is the force and \( v \) is the velocity. \( P = 200 \text{ N} \times 5 \text{ m/s} = 1000 \text{ W} \).
216. Why is power considered a scalar quantity in physics?
ⓐ. It has direction
ⓑ. It has magnitude
ⓒ. It represents energy
ⓓ. It indicates velocity
Correct Answer: It has magnitude
Explanation: Power is a scalar quantity because it has magnitude (amount or size) but does not have direction like vector quantities such as force or velocity.
217. Which situation represents the highest power output?
ⓐ. Lifting a 10 kg weight 1 m in 10 seconds
ⓑ. Lifting a 5 kg weight 2 m in 5 seconds
ⓒ. Lifting a 2 kg weight 3 m in 6 seconds
ⓓ. Lifting a 1 kg weight 4 m in 8 seconds
Correct Answer: Lifting a 5 kg weight 2 m in 5 seconds
Explanation: Power is calculated as the rate of doing work. The situation with the highest power output would involve lifting the most weight the furthest in the shortest time.
218. Which device converts mechanical energy into electrical energy most efficiently?
ⓐ. Solar panel
ⓑ. Wind turbine
ⓒ. Generator
ⓓ. Battery
Correct Answer: Generator
Explanation: A generator is designed to convert mechanical energy (often from rotation) into electrical energy efficiently, based on its power output.
219. What happens to power output if the time taken to do work decreases while the amount of work done remains constant?
ⓐ. Power decreases
ⓑ. Power remains constant
ⓒ. Power increases
ⓓ. Power becomes zero
Correct Answer: Power increases
Explanation: Power is inversely proportional to time \( t \). As \( t \) decreases, \( P = \frac{W}{t} \) increases, assuming work \( W \) remains constant.
220. How does power relate to the ability to perform tasks quickly in physics?
ⓐ. Higher power allows tasks to be performed more slowly
ⓑ. Higher power allows tasks to be performed more quickly
ⓒ. Power has no effect on task performance
ⓓ. Power is related to gravitational forces
Correct Answer: Higher power allows tasks to be performed more quickly
Explanation: Power represents the rate at which work is done. Higher power means tasks can be completed more quickly because more work is done per unit time.
221. What is the SI unit of power?
ⓐ. Joule
ⓑ. Watt
ⓒ. Newton
ⓓ. Tesla
Correct Answer: Watt
Explanation: The SI unit of power is the watt (W), named after James Watt.
222. Which of the following is a non-SI unit of power commonly used in the context of engines and motors?
ⓐ. Joule
ⓑ. Watt
ⓒ. Horsepower
ⓓ. Newton
Correct Answer: Horsepower
Explanation: Horsepower (hp) is a non-SI unit of power commonly used to measure the power output of engines and motors.
223. Convert 1 horsepower (hp) into watts (W).
ⓐ. 500 W
ⓑ. 746 W
ⓒ. 1000 W
ⓓ. 1500 W
Correct Answer: 746 W
Explanation: 1 horsepower (hp) is equivalent to approximately 746 watts (W).
224. A device operates at 5000 watts (W). What is its power output in kilowatts (kW)?
ⓐ. 5 kW
ⓑ. 50 kW
ⓒ. 500 kW
ⓓ. 5000 kW
Correct Answer: 5 kW
Explanation: 1 kilowatt (kW) = 1000 watts (W). Therefore, 5000 W = 5 kW.
225. Which unit of power is commonly used to measure the power output of electric appliances?
ⓐ. Horsepower
ⓑ. Kilowatt
ⓒ. Tesla
ⓓ. Newton
Correct Answer: Kilowatt
Explanation: Kilowatt (kW) is commonly used to measure the power output of electric appliances due to the practical range of power consumption.
226. A light bulb has a power rating of 60 watts (W). How much energy does it consume in 5 hours?
ⓐ. 300 J
ⓑ. 3000 J
ⓒ. 30000 J
ⓓ. 300000 J
Correct Answer: 300000 J
Explanation: Energy consumed \( E = P \times t = 60 \text{ W} \times (5 \text{ hours} \times 3600 \text{ s/hour}) = 300000 \text{ J} \).
227. What is the relationship between horsepower (hp) and kilowatts (kW)?
ⓐ. 1 hp = 100 kW
ⓑ. 1 hp = 746 kW
ⓒ. 1 hp = 1000 kW
ⓓ. 1 hp = 5000 kW
Correct Answer: 1 hp = 746 kW
Explanation: 1 horsepower (hp) is approximately equal to 746 watts (W), which equals 0.746 kilowatts (kW).
228. Which unit of power is commonly used in the context of gravitational forces and mechanical work?
ⓐ. Horsepower
ⓑ. Kilowatt
ⓒ. Newton
ⓓ. Tesla
Correct Answer: Horsepower
Explanation: Horsepower (hp) is commonly used in contexts involving engines, mechanical work, and gravitational forces.
229. What is the power output of a device that does 500 joules of work in 10 seconds?
ⓐ. 5 W
ⓑ. 50 W
ⓒ. 500 W
ⓓ. 5000 W
Correct Answer: 50 W
Explanation: Power \( P = \frac{W}{t} = \frac{500 \text{ J}}{10 \text{ s}} = 50 \text{ W} \).
230. Which unit of power is named after the Scottish engineer who played a significant role in the development of steam engines?
ⓐ. Watt
ⓑ. Newton
ⓒ. Tesla
ⓓ. Joule
Correct Answer: Watt
Explanation: The watt (W) is named after James Watt, a Scottish engineer who made important contributions to the development of steam engines.
231. What is the relationship between power, work, and time?
ⓐ. Power = Work / Time
ⓑ. Power = Work + Time
ⓒ. Power = Work × Time
ⓓ. Power = Time / Work
Correct Answer: Power = Work / Time
Explanation: Power is defined as the rate at which work is done, which is calculated as \( P = \frac{W}{t} \), where \( W \) is the work done and \( t \) is the time taken.
232. If a machine does 600 joules of work in 3 seconds, what is its power output?
ⓐ. 100 W
ⓑ. 200 W
ⓒ. 300 W
ⓓ. 400 W
Correct Answer: 200 W
Explanation: \( P = \frac{W}{t} = \frac{600 \text{ J}}{3 \text{ s}} = 200 \text{ W} \).
233. A car engine does 240,000 joules of work in 20 seconds. What is its average power output?
ⓐ. 10 W
ⓑ. 1000 W
ⓒ. 12,000 W
ⓓ. 48,000 W
Correct Answer: 12,000 W
Explanation: \( P = \frac{W}{t} = \frac{240000 \text{ J}}{20 \text{ s}} = 12000 \text{ W} \).
234. What happens to power if the work done remains constant but the time taken is increased?
ⓐ. Power decreases
ⓑ. Power remains constant
ⓒ. Power increases
ⓓ. Power becomes zero
Correct Answer: Power decreases
Explanation: Power is inversely proportional to time \( t \). If \( t \) increases while \( W \) remains constant, \( P = \frac{W}{t} \) decreases.
235. Which situation describes higher power output?
ⓐ. Lifting a 10 kg weight 2 meters in 5 seconds
ⓑ. Lifting a 5 kg weight 4 meters in 10 seconds
ⓒ. Lifting a 2 kg weight 3 meters in 6 seconds
ⓓ. Lifting a 1 kg weight 6 meters in 12 seconds
Correct Answer: Lifting a 5 kg weight 4 meters in 10 seconds
Explanation: Power is calculated as \( P = \frac{W}{t} \). The situation with the most work done in the least time has the highest power output.
236. A pump does 1200 joules of work in 30 seconds. What is its power output in kilowatts (kW)?
ⓐ. 0.04 kW
ⓑ. 0.4 kW
ⓒ. 4 kW
ⓓ. 40 kW
Correct Answer: 0.4 kW
Explanation: First, calculate power in watts: \( P = \frac{W}{t} = \frac{1200 \text{ J}}{30 \text{ s}} = 40 \text{ W} \). Then convert to kilowatts (kW): \( 0.4 \text{ kW} \).
237. Which formula represents the relationship between power, work, and time?
ⓐ. \( P = \frac{W}{t} \)
ⓑ. \( P = W \times t \)
ⓒ. \( P = W – t \)
ⓓ. \( P = \frac{t}{W} \)
Correct Answer: \( P = \frac{W}{t} \)
Explanation: Power \( P \) is defined as the amount of work \( W \) done divided by the time \( t \) taken to do that work.
238. What is the power output if a device does 8000 joules of work in 20 seconds?
ⓐ. 400 W
ⓑ. 800 W
ⓒ. 1600 W
ⓓ. 4000 W
Correct Answer: 400 W
Explanation: \( P = \frac{W}{t} = \frac{8000 \text{ J}}{20 \text{ s}} = 400 \text{ W} \).
239. A motor lifts a 50 kg weight to a height of 10 meters in 5 seconds. What is the power output of the motor?
ⓐ. 930 W
ⓑ. 910 W
ⓒ. 980 W
ⓓ. 1000 W
Correct Answer: 980 W
Explanation: First, calculate work \( W = mgh = 50 \text{ kg} \times 9.8 \text{ m/s}^2 \times 10 \text{ m} = 4900 \text{ J} \). Then, calculate power \( P = \frac{W}{t} = \frac{4900 \text{ J}}{5 \text{ s}} = 980 \text{ W} \).
240. What is the power output if a device does 240 joules of work in 12 seconds?
ⓐ. 5 W
ⓑ. 10 W
ⓒ. 15 W
ⓓ. 20 W
Correct Answer: 20 W
Explanation: \( P = \frac{W}{t} = \frac{240 \text{ J}}{12 \text{ s}} = 20 \text{ W} \).
241. What is potential energy?
ⓐ. Energy stored in motion
ⓑ. Energy of an object due to its position
ⓒ. Energy of an object due to its velocity
ⓓ. Energy of an object due to its temperature
Correct Answer: Energy of an object due to its position
Explanation: Potential energy is the energy possessed by an object due to its position or configuration relative to other objects.
242. Which of the following is an example of gravitational potential energy?
ⓐ. A moving car
ⓑ. A stretched rubber band
ⓒ. A spinning top
ⓓ. A book on a shelf
Correct Answer: A book on a shelf
Explanation: Gravitational potential energy is associated with the position of an object relative to the Earth or another massive body.
243. What type of energy does a stretched spring possess?
ⓐ. Kinetic energy
ⓑ. Thermal energy
ⓒ. Potential energy
ⓓ. Magnetic energy
Correct Answer: Potential energy
Explanation: A stretched spring possesses elastic potential energy due to its deformation from its equilibrium position.
244. In the context of chemical reactions, what is potential energy often referred to as?
ⓐ. Activation energy
ⓑ. Thermal energy
ⓒ. Electrical energy
ⓓ. Nuclear energy
Correct Answer: Activation energy
Explanation: In chemistry, potential energy is often referred to as activation energy, which is the energy required to initiate a chemical reaction.
245. What form of energy is associated with a charged particle in an electric field?
ⓐ. Mechanical energy
ⓑ. Chemical energy
ⓒ. Electrical potential energy
ⓓ. Nuclear energy
Correct Answer: Electrical potential energy
Explanation: A charged particle in an electric field possesses electrical potential energy due to its position in the field.
246. What type of potential energy is stored in a dam?
ⓐ. Chemical potential energy
ⓑ. Gravitational potential energy
ⓒ. Nuclear potential energy
ⓓ. Magnetic potential energy
Correct Answer: Gravitational potential energy
Explanation: A dam stores water at an elevated height, allowing it to possess gravitational potential energy.
247. Which factor primarily determines the amount of gravitational potential energy possessed by an object?
ⓐ. Its mass
ⓑ. Its volume
ⓒ. Its shape
ⓓ. Its color
Correct Answer: Its mass
Explanation: Gravitational potential energy \( E_p = mgh \), where \( m \) is mass, \( g \) is acceleration due to gravity, and \( h \) is height.
248. What is the formula for calculating elastic potential energy in a stretched spring?
ⓐ. \( E_p = \frac{1}{2} kx^2 \)
ⓑ. \( E_p = \frac{1}{2} mv^2 \)
ⓒ. \( E_p = mgh \)
ⓓ. \( E_p = Fd \)
Correct Answer: \( E_p = \frac{1}{2} kx^2 \)
Explanation: \( E_p \) is elastic potential energy, \( k \) is the spring constant, and \( x \) is the displacement from equilibrium.
249. What does the term “potential” refer to in potential energy?
ⓐ. Stored energy
ⓑ. Moving energy
ⓒ. Fixed energy
ⓓ. Gravitational energy
Correct Answer: Stored energy
Explanation: Potential energy refers to stored energy that an object possesses due to its position or configuration.
250. Which law of physics relates the conservation of mechanical energy to potential energy?
ⓐ. Newton’s First Law
ⓑ. Ohm’s Law
ⓒ. Law of Conservation of Energy
ⓓ. Hooke’s Law
Correct Answer: Law of Conservation of Energy
Explanation: The Law of Conservation of Energy states that energy cannot be created or destroyed, only transferred or converted from one form to another.
251. What is elastic potential energy?
ⓐ. Energy stored in a moving object
ⓑ. Energy stored in an object due to its mass
ⓒ. Energy stored in a stretched or compressed spring
ⓓ. Energy stored in a rotating object
Correct Answer: Energy stored in a stretched or compressed spring
Explanation: Elastic potential energy is the energy stored in a stretched or compressed elastic object, such as a spring.
252. What is the formula for calculating elastic potential energy in a spring?
ⓐ. \( E_p = \frac{1}{2} kx^2 \)
ⓑ. \( E_p = \frac{1}{2} mv^2 \)
ⓒ. \( E_p = mgh \)
ⓓ. \( E_p = Fd \)
Correct Answer: \( E_p = \frac{1}{2} kx^2 \)
Explanation: \( E_p \) is elastic potential energy, \( k \) is the spring constant, and \( x \) is the displacement from equilibrium.
253. If a spring is stretched 0.2 meters from its equilibrium position and has a spring constant of 50 N/m, what is its elastic potential energy?
ⓐ. 0.5 J
ⓑ. 2.0 J
ⓒ. 5.0 J
ⓓ. 10.0 J
Correct Answer: 2.0 J
Explanation: \( E_p = \frac{1}{2} kx^2 = \frac{1}{2} \times 50 \text{ N/m} \times (0.2 \text{ m})^2 = 2.0 \text{ J} \).
254. Which factor affects the elastic potential energy stored in a spring?
ⓐ. Length of the spring
ⓑ. Material of the spring
ⓒ. Temperature of the spring
ⓓ. Spring constant
Correct Answer: Spring constant
Explanation: Elastic potential energy in a spring depends on its spring constant \( k \) and the displacement from equilibrium \( x \).
255. If the displacement of a spring is doubled, how does the elastic potential energy change?
ⓐ. It doubles
ⓑ. It quadruples
ⓒ. It halves
ⓓ. It remains the same
Correct Answer: It quadruples
Explanation: \( E_p = \frac{1}{2} kx^2 \). Doubling \( x \) quadruples \( E_p \), assuming \( k \) remains constant.
256. What happens to the elastic potential energy of a spring if its spring constant is doubled?
ⓐ. It doubles
ⓑ. It quadruples
ⓒ. It halves
ⓓ. It remains the same
Correct Answer: It remains the same
Explanation: \( E_p = \frac{1}{2} kx^2 \). Changing \( k \) affects force but not \( E_p \) for a given \( x \).
257. What unit is used to measure elastic potential energy?
ⓐ. Joule (J)
ⓑ. Newton (N)
ⓒ. Meter (m)
ⓓ. Pascal (Pa)
Correct Answer: Joule (J)
Explanation: Elastic potential energy, like other forms of energy, is measured in joules (J).
258. What form of potential energy is stored in a compressed spring?
ⓐ. Gravitational potential energy
ⓑ. Elastic potential energy
ⓒ. Nuclear potential energy
ⓓ. Magnetic potential energy
Correct Answer: Elastic potential energy
Explanation: A compressed spring stores elastic potential energy due to its deformation from its equilibrium position.
259. If the displacement of a spring is halved, how does the elastic potential energy change?
ⓐ. It doubles
ⓑ. It halves
ⓒ. It quadruples
ⓓ. It remains the same
Correct Answer: It halves
Explanation: \( E_p = \frac{1}{2} kx^2 \). Halving \( x \) reduces \( E_p \) to one-fourth, assuming \( k \) remains constant.
260. Which law of physics is used to calculate elastic potential energy in a spring?
ⓐ. Hooke’s Law
ⓑ. Newton’s First Law
ⓒ. Faraday’s Law
ⓓ. Ohm’s Law
Correct Answer: Hooke’s Law
Explanation: Hooke’s Law relates the force exerted by a spring to its displacement, which is essential for calculating elastic potential energy.
261. What is the principle of conservation of mechanical energy?
ⓐ. Mechanical energy can be created or destroyed.
ⓑ. Mechanical energy can be transformed from one form to another without loss.
ⓒ. The total mechanical energy of an isolated system remains constant.
ⓓ. Mechanical energy is independent of potential and kinetic energy.
Correct Answer: The total mechanical energy of an isolated system remains constant.
Explanation: The principle of conservation of mechanical energy states that in an isolated system, the total mechanical energy (the sum of potential and kinetic energy) remains constant as long as only conservative forces are acting.
262. In the absence of non-conservative forces, what happens to the mechanical energy of a system?
ⓐ. It increases.
ⓑ. It decreases.
ⓒ. It remains constant.
ⓓ. It fluctuates.
Correct Answer: It remains constant.
Explanation: In the absence of non-conservative forces such as friction or air resistance, the total mechanical energy of a system remains constant, according to the principle of conservation of mechanical energy.
263. Which of the following forces is considered conservative?
ⓐ. Friction
ⓑ. Air resistance
ⓒ. Gravitational force
ⓓ. Tension
Correct Answer: Gravitational force
Explanation: Gravitational force is a conservative force, meaning that the work done by or against it is path-independent and can be fully recovered.
264. A roller coaster car starts from rest at a height of 50 meters. Assuming no friction, what happens to its potential energy as it descends?
ⓐ. It increases.
ⓑ. It decreases.
ⓒ. It remains constant.
ⓓ. It converts into thermal energy.
Correct Answer: It decreases.
Explanation: As the roller coaster car descends, its gravitational potential energy decreases and is converted into kinetic energy, maintaining the total mechanical energy of the system.
265. If a pendulum is released from a height of 1 meter, what can be said about its kinetic energy at the lowest point of its swing?
ⓐ. It is zero.
ⓑ. It is maximum.
ⓒ. It is equal to its potential energy at the highest point.
ⓓ. It is equal to the total mechanical energy.
Correct Answer: It is maximum.
Explanation: At the lowest point of its swing, the pendulum’s kinetic energy is maximum because its potential energy is at a minimum, and the total mechanical energy is conserved.
266. In an isolated system, if the kinetic energy of an object decreases, what must happen to its potential energy?
ⓐ. It must decrease.
ⓑ. It must increase.
ⓒ. It must remain the same.
ⓓ. It is not related to kinetic energy.
Correct Answer: It must increase.
Explanation: In an isolated system, if the kinetic energy decreases, the potential energy must increase to keep the total mechanical energy constant.
267. A projectile is launched vertically upward. Ignoring air resistance, what happens to its kinetic energy as it reaches the highest point?
ⓐ. It becomes zero.
ⓑ. It becomes maximum.
ⓒ. It becomes equal to its initial kinetic energy.
ⓓ. It becomes equal to its potential energy.
Correct Answer: It becomes zero.
Explanation: At the highest point of its trajectory, the projectile’s velocity is zero, so its kinetic energy is zero, and all its initial kinetic energy has been converted into potential energy.
268. What happens to the total mechanical energy of a system when only conservative forces are acting?
ⓐ. It increases.
ⓑ. It decreases.
ⓒ. It remains constant.
ⓓ. It converts into non-mechanical forms of energy.
Correct Answer: It remains constant.
Explanation: When only conservative forces are acting on a system, the total mechanical energy remains constant because the energy can be converted between kinetic and potential forms without any loss.
269. Which of the following best describes the work done by a conservative force?
ⓐ. It depends on the path taken.
ⓑ. It depends on the initial and final positions only.
ⓒ. It is always zero.
ⓓ. It is always positive.
Correct Answer: It depends on the initial and final positions only.
Explanation: The work done by a conservative force is path-independent and depends only on the initial and final positions of the object.
270. If a block slides down a frictionless inclined plane, what happens to its potential energy?
ⓐ. It increases.
ⓑ. It decreases.
ⓒ. It remains the same.
ⓓ. It converts into thermal energy.
Correct Answer: It decreases.
Explanation: As the block slides down the inclined plane, its gravitational potential energy decreases and is converted into kinetic energy, maintaining the conservation of mechanical energy.
271. A pendulum swings from a height of 2 meters. Assuming no air resistance, what happens to the potential energy at the lowest point of the swing?
ⓐ. It becomes zero.
ⓑ. It is converted entirely to kinetic energy.
ⓒ. It becomes maximum.
ⓓ. It remains constant.
Correct Answer: It is converted entirely to kinetic energy.
Explanation: At the lowest point of its swing, all the pendulum’s potential energy has been converted to kinetic energy, demonstrating the conservation of mechanical energy.
272. In a frictionless roller coaster, a car starts at the top of a hill with a certain amount of potential energy. What happens to this energy as the car descends?
ⓐ. It decreases.
ⓑ. It remains the same.
ⓒ. It is converted to kinetic energy.
ⓓ. It is lost to the environment.
Correct Answer: It is converted to kinetic energy.
Explanation: As the roller coaster car descends, its potential energy decreases and is converted to kinetic energy, keeping the total mechanical energy constant.
273. A block is dropped from a height of 10 meters. Neglecting air resistance, what happens to the block’s kinetic energy just before it hits the ground?
ⓐ. It is at its maximum.
ⓑ. It is zero.
ⓒ. It is equal to its initial potential energy.
ⓓ. It is half of its initial potential energy.
Correct Answer: It is at its maximum.
Explanation: Just before hitting the ground, the block’s potential energy has been completely converted to kinetic energy, which is at its maximum.
274. In a perfectly elastic collision, what happens to the mechanical energy of the system?
ⓐ. It is lost.
ⓑ. It remains constant.
ⓒ. It is converted to thermal energy.
ⓓ. It is partially conserved.
Correct Answer: It remains constant.
Explanation: In a perfectly elastic collision, both kinetic energy and mechanical energy are conserved, meaning the total mechanical energy remains constant.
275. A skier starts from rest at the top of a slope. Ignoring friction, what happens to the skier’s potential energy as they descend?
ⓐ. It increases.
ⓑ. It decreases.
ⓒ. It remains the same.
ⓓ. It is converted into heat.
Correct Answer: It decreases.
Explanation: As the skier descends, their potential energy decreases and is converted to kinetic energy, illustrating the conservation of mechanical energy.
276. A compressed spring is used to launch a toy car. What happens to the potential energy stored in the spring?
ⓐ. It is destroyed.
ⓑ. It is converted to kinetic energy of the car.
ⓒ. It remains potential energy.
ⓓ. It is lost as sound energy.
Correct Answer: It is converted to kinetic energy of the car.
Explanation: When the spring is released, its stored potential energy is converted into the kinetic energy of the toy car.
277. A ball is thrown vertically upward with an initial velocity. At its highest point, what can be said about its kinetic and potential energy?
ⓐ. Kinetic energy is zero, and potential energy is maximum.
ⓑ. Both kinetic and potential energy are zero.
ⓒ. Kinetic energy is maximum, and potential energy is zero.
ⓓ. Both kinetic and potential energy are maximum.
Correct Answer: Kinetic energy is zero, and potential energy is maximum.
Explanation: At the highest point, the ball’s velocity is zero, so its kinetic energy is zero, and its potential energy is at a maximum.
278. A roller coaster car is at the top of a loop-the-loop. Assuming no friction, what happens to its total mechanical energy as it moves through the loop?
ⓐ. It increases.
ⓑ. It decreases.
ⓒ. It remains constant.
ⓓ. It fluctuates.
Correct Answer: It remains constant.
Explanation: Assuming no friction, the roller coaster car’s total mechanical energy remains constant as it moves through the loop, converting between kinetic and potential energy.
279. In a pendulum clock, what happens to the kinetic energy when the pendulum reaches its lowest point?
ⓐ. It is maximum.
ⓑ. It is zero.
ⓒ. It is equal to the potential energy at the highest point.
ⓓ. It is half of the total energy.
Correct Answer: It is maximum.
Explanation: At the pendulum’s lowest point, its kinetic energy is at a maximum as all its potential energy has been converted to kinetic energy.
280. When a person jumps on a trampoline, what happens to their kinetic energy as they reach the maximum height of the jump?
ⓐ. It is at its maximum.
ⓑ. It is zero.
ⓒ. It is equal to the potential energy at the lowest point.
ⓓ. It fluctuates.
Correct Answer: It is zero.
Explanation: At the maximum height of the jump, the person’s velocity is zero, so their kinetic energy is zero, and all the energy has been converted to potential energy.
281. A satellite orbits Earth in a circular path. Assuming no external forces, what happens to the satellite’s total mechanical energy?
ⓐ. It increases.
ⓑ. It decreases.
ⓒ. It remains constant.
ⓓ. It fluctuates.
Correct Answer: It remains constant.
Explanation: In the absence of external forces, the total mechanical energy of the satellite remains constant, demonstrating the conservation of mechanical energy in orbital motion.
282. A car accelerates from rest down a frictionless hill. What conservation law explains the conversion of potential energy to kinetic energy?
ⓐ. Conservation of mass
ⓑ. Conservation of mechanical energy
ⓒ. Conservation of momentum
ⓓ. Conservation of charge
Correct Answer: Conservation of mechanical energy
Explanation: The conservation of mechanical energy explains how the car’s potential energy at the top of the hill is converted into kinetic energy as it accelerates down the hill.
283. A skier starts from rest at the top of a frictionless slope. Using conservation laws, what can you predict about the skier’s speed at the bottom of the slope?
ⓐ. It will be zero.
ⓑ. It will be maximum.
ⓒ. It will be constant.
ⓓ. It cannot be predicted.
Correct Answer: It will be maximum.
Explanation: The conservation of mechanical energy allows us to predict that the skier’s potential energy at the top of the slope will be converted into maximum kinetic energy at the bottom, resulting in maximum speed.
284. A pendulum is released from a certain height. At what point in its swing is the conservation of mechanical energy most evident?
ⓐ. At the highest point
ⓑ. At the lowest point
ⓒ. At the midpoint
ⓓ. Throughout the swing
Correct Answer: Throughout the swing
Explanation: The conservation of mechanical energy is evident throughout the pendulum’s swing as potential energy is converted to kinetic energy and vice versa, maintaining constant total mechanical energy.
285. In a hydroelectric power plant, water stored at height is released to generate electricity. What conservation principle is utilized in this process?
ⓐ. Conservation of mass
ⓑ. Conservation of mechanical energy
ⓒ. Conservation of momentum
ⓓ. Conservation of charge
Correct Answer: Conservation of mechanical energy
Explanation: The conservation of mechanical energy principle is utilized, where the potential energy of the stored water is converted into kinetic energy, which is then used to generate electricity.
286. A roller coaster is designed to convert potential energy into kinetic energy and vice versa. What must be true for the conservation of mechanical energy to hold in this system?
ⓐ. The roller coaster must be powered by an engine.
ⓑ. Friction and air resistance must be negligible.
ⓒ. The roller coaster must have loops.
ⓓ. The roller coaster must be made of steel.
Correct Answer: Friction and air resistance must be negligible.
Explanation: For the conservation of mechanical energy to hold, friction and air resistance must be negligible so that there are no non-conservative forces doing work on the system.
287. A diver jumps off a diving board with an initial horizontal velocity. What conservation law explains the relationship between his potential and kinetic energy as he falls?
ⓐ. Conservation of mass
ⓑ. Conservation of mechanical energy
ⓒ. Conservation of momentum
ⓓ. Conservation of charge
Correct Answer: Conservation of mechanical energy
Explanation: The conservation of mechanical energy explains how the diver’s potential energy at the top is converted to kinetic energy as he falls.
288. A compressed spring is used to launch a ball horizontally. Which conservation law can be used to analyze the energy conversion in this scenario?
ⓐ. Conservation of mass
ⓑ. Conservation of mechanical energy
ⓒ. Conservation of momentum
ⓓ. Conservation of charge
Correct Answer: Conservation of mechanical energy
Explanation: The conservation of mechanical energy can be used to analyze how the potential energy stored in the compressed spring is converted to the kinetic energy of the ball.
289. A cyclist coasts down a hill without pedaling or braking. Assuming negligible air resistance and friction, how does the conservation of mechanical energy apply?
ⓐ. Potential energy is converted into kinetic energy.
ⓑ. Kinetic energy is converted into potential energy.
ⓒ. Both A and B.
ⓓ. Neither A nor B.
Correct Answer: Potential energy is converted into kinetic energy.
Explanation: As the cyclist coasts down the hill, their potential energy is converted into kinetic energy, illustrating the conservation of mechanical energy.
290. An archer pulls back a bowstring, storing energy in the bow. When the arrow is released, what conservation law describes the energy transformation?
ⓐ. Conservation of mass
ⓑ. Conservation of mechanical energy
ⓒ. Conservation of momentum
ⓓ. Conservation of charge
Correct Answer: Conservation of mechanical energy
Explanation: The conservation of mechanical energy describes how the potential energy stored in the drawn bow is converted into the kinetic energy of the released arrow.
291. What is Hooke’s Law?
ⓐ. F = ma
ⓑ. F = kx
ⓒ. F = mg
ⓓ. F = 1/2 kx^2
Correct Answer: F = kx
Explanation: Hooke’s Law states that the force exerted by a spring is directly proportional to the displacement from its equilibrium position, where F is the force, k is the spring constant, and x is the displacement.
292. Which of the following best describes the spring constant (k) in Hooke’s Law?
ⓐ. A measure of the spring’s mass
ⓑ. A measure of the spring’s displacement
ⓒ. A measure of the spring’s stiffness
ⓓ. A measure of the spring’s length
Correct Answer: A measure of the spring’s stiffness
Explanation: The spring constant (k) is a measure of the stiffness of the spring. A larger k value indicates a stiffer spring, which requires more force to displace.
293. What is the potential energy stored in a spring (elastic potential energy) when it is compressed or stretched by a displacement x?
ⓐ. U = kx
ⓑ. U = 1/2 kx^2
ⓒ. U = kx^2
ⓓ. U = 1/2 kx
Correct Answer: U = 1/2 kx^2
Explanation: The elastic potential energy stored in a spring when it is compressed or stretched by a displacement x is given by U = 1/2 kx^2, where k is the spring constant.
294. If a spring with a spring constant k is compressed by 0.5 meters, how does the potential energy change if the compression is doubled?
ⓐ. It remains the same
ⓑ. It doubles
ⓒ. It quadruples
ⓓ. It halves
Correct Answer: It quadruples
Explanation: Since elastic potential energy is proportional to the square of the displacement (U = 1/2 kx^2), doubling the displacement results in a fourfold increase in potential energy.
295. A spring has a spring constant of 200 N/m. What is the elastic potential energy stored when the spring is stretched by 0.2 meters?
ⓐ. 2 J
ⓑ. 4 J
ⓒ. 8 J
ⓓ. 10 J
Correct Answer: 4 J
Explanation: The elastic potential energy is calculated using U = 1/2 kx^2. Substituting k = 200 N/m and x = 0.2 m, we get U = 1/2 * 200 * (0.2)^2 = 4 J.
296. Two identical springs are compressed by different amounts. Spring A is compressed by 0.1 meters and Spring B by 0.2 meters. How does the elastic potential energy stored in Spring B compare to that in Spring A?
ⓐ. Twice as much
ⓑ. Half as much
ⓒ. Four times as much
ⓓ. The same amount
Correct Answer: Four times as much
Explanation: The elastic potential energy stored in a spring is proportional to the square of the displacement (U = 1/2 kx^2). Doubling the displacement results in a fourfold increase in potential energy.
297. What happens to the elastic potential energy if the spring constant is halved while keeping the displacement constant?
ⓐ. It remains the same
ⓑ. It doubles
ⓒ. It halves
ⓓ. It reduces to one-fourth
Correct Answer: It halves
Explanation: Elastic potential energy is given by U = 1/2 kx^2. Halving the spring constant k while keeping the displacement x constant results in halving the potential energy.
298. Which of the following is true about the work done by a spring when it is stretched or compressed?
ⓐ. It is equal to the elastic potential energy stored in the spring
ⓑ. It is greater than the elastic potential energy stored in the spring
ⓒ. It is less than the elastic potential energy stored in the spring
ⓓ. It is unrelated to the elastic potential energy stored in the spring
Correct Answer: It is equal to the elastic potential energy stored in the spring
Explanation: The work done by a spring when it is stretched or compressed is equal to the elastic potential energy stored in the spring (U = 1/2 kx^2).
299. A mass-spring system oscillates with a maximum displacement of 0.3 meters and a spring constant of 100 N/m. What is the maximum elastic potential energy stored in the spring?
ⓐ. 3.5 J
ⓑ. 4.5 J
ⓒ. 6.5 J
ⓓ. 9 J
Correct Answer: 4.5 J
Explanation: The maximum elastic potential energy is given by U = 1/2 kx^2. Substituting k = 100 N/m and x = 0.3 m, we get U = 1/2 * 100 * (0.3)^2 = 4.5 J.
300. In a spring-mass system, what is the relationship between the maximum kinetic energy and the maximum elastic potential energy during oscillation?
ⓐ. Maximum kinetic energy is greater
ⓑ. Maximum elastic potential energy is greater
ⓒ. They are equal
ⓓ. No fixed relationship
Correct Answer: They are equal
Explanation: In a spring-mass system undergoing simple harmonic motion, the maximum kinetic energy is equal to the maximum elastic potential energy due to the conservation of mechanical energy.
The topic Work, Energy, and Power forms a major section of NCERT/CBSE Class 11 Physics, frequently appearing in board exams and highly relevant for competitive exams like JEE, NEET, and other entrance tests. This chapter explains critical principles such as conservative and non-conservative forces, energy transformations, and practical problem-solving based on the work-energy theorem. Out of a total of 420 MCQs with solutions, this section (Part 3) provides the next 100 questions, each explained in detail to improve accuracy and confidence.
- 👉 Total MCQs in this chapter: 420.
- 👉 This page contains: Third set of 100 solved MCQs.
- 👉 Important for board exams and competitive tests (JEE/NEET).
- 👉 Use the top navigation bar to explore other chapters and subjects.
- 👉 To practice the next 100 questions, click the Part 4 button above.