Free Work and Energy MCQs with Answers
748 Work and Energy MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Work transfers energy when a force causes displacement, while kinetic energy, gravitational potential energy and power describe motion, position and the rate of energy transfer. The work-energy theorem links net work with change in kinetic energy, and efficiency accounts for energy losses rather than treating them as energy destruction.
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Read the Work and Energy notesFree MDCAT chapter notes with key terms748 questions · page 37 of 38
- A. Pushing a car to start it moving
- B. Lifting the weights.
- C. The moon Orbiting the earth.
- D. Writing an essay on a page.
Explanation: When the moon revolves around the earth, the displacement is normal to the direction of force on the moon.
Correct answer: The moon Orbiting the earth.- A. Force into small intervals
- B. The displacement into small intervals
- C. Both force and displacement into small intervals
- D. By taking displacements at different angles
Explanation: The work done by a variable force is calculated by integrating the force over the displacement.
Correct answer: The displacement into small intervals- A. Frictional force
- B. Effort + distance
- C. Effort-distance
- D. Effort +distance
Explanation: Frictional force is a non-conservative force.due to its energy-dissipating nature and the path-dependent work it entails.
Correct answer: Frictional force- A. 1J
- B. 10J
- C. 0J
- D. 100J
Explanation: The formula for work done (W) is:W=F×d×cosθW = F \times d \times \cos\thetaW=F×d×cosθWhere:W = Work done (in Joules)F = Force (in…
Correct answer: 1J- A. m1:m2
- B. √m1/m2
- C. m1²: m2²
- D. √m1:√m2
Explanation: The energy and momentum are related The KE is proportional to square of momentum KE = p²/2m so if two bodies have equal energy then their…
Correct answer: √m1/m2- A. 12
- B. 144
- C. 72
- D. 48
Explanation: To determine the kinetic energy of the mass after 4 seconds, apply Newton's second law.
Correct answer: 144- A. 44%
- B. 36%
- C. 28%
- D. 20%
Explanation: Momentum p = mvIf momentum is decreased by 20%, the resulting new value is 80% of the original p-p'P - 0.2p = mv - m0.2vP - 0.2p = (m) (v)…
Correct answer: 36%- A. 4800 J
- B. 3500 J
- C. 1200 J
- D. 120 J
Explanation: To find the kinetic energy of the block when it has fallen 60m, we need to calculate the change in potential energy as it falls.
Correct answer: 1200 J- A. Weighs more than P
- B. Is moving faster than P
- C. Weighs the same as P
- D. Is moving slower than P
Explanation: To determine which object has more kinetic energy when two objects have the same momentum, examine their speeds.
Correct answer: Is moving faster than P- A. His height above the ground
- B. His mass
- C. Elevator's speed
- D. Elevator's direction of movement
Explanation: The primary factor that determines the man's kinetic energy is the elevator's speed.
Correct answer: Elevator's speed- A. Gravitational forces and elastic forces
- B. Frictional force and propulsion of a motor
- C. electric force and tensioning string
- D. propulsion force of rocket and air resistence
Explanation: There are conservative and non-conservative forces. A conservative force is not path dependent, such as gravity and electrostatic forces.
Correct answer: Gravitational forces and elastic forces- A. All of these
- B. Zero
- C. Positive
- D. Negative
Explanation: The work done by the spring force can be positive, negative, or zero depending on the direction of motion and position of the particle.
Correct answer: All of these- A. E/2
- B. 2E
- C. E
- D. E/4
Explanation: EA = ½ kAxA2 Keeping force constant and using F= kx As kA = 2kB Then 2xA=xB Energy stored in B will be: EB= ½ (kA/2) (2xA)2 EB= ½ (2xA2…
Correct answer: 2E- A. 3:4
- B. 4:3
- C. 1:1
- D. None
Explanation: Factual. Gravitational potential for an equipotential surface (one that is at same height) is same for all masses. Hence ratio will be 1:1
Correct answer: 1:1- A. 98 J
- B. 49J
- C. 490 J
- D. 980 J
Explanation: The potential energy (PE) stored in an object is calculated as:PE = m × g × hwhere:m = mass of the object (10 kg)g = acceleration due to…
Correct answer: 490 J- A. 2.4 watts
- B. 120 watts
- C. 60 watts
- D. 300 watts
Explanation: The question is asking for the watt or power of the lamp. We know that P = IV and we are given that I = 5 amps and V = 12 volts.
Correct answer: 60 watts737. If an amount of work △W is done by an agent in time interval △t, the power of that agency Will be:
- A. △W /△t
- B. △t / W△
- C. △t / △W
- D. △W + △t
Explanation: Thus power is defined as the rate of transfer of energy. In other words, we also define power.
Correct answer: △W /△t- A. power
- B. impulse
- C. couple
- D. Momentum
Explanation: Velocity=distance/time Force x velocity can also be written as force x distance or time force x distance = work done so the formula can be…
Correct answer: power- A. 1.2 kW
- B. 12kW
- C. 120kW
- D. 1200kW
Explanation: Students should remember the formula of power i.e Force x speed So power = (mass x g) x speed assume g = 10] Power = (40 x 10) x 3 = 1200…
Correct answer: 1.2 kW- A. 1
- B. 16/25
- C. 25/16
- D. 4/5
Explanation: Power of first boy / Power of second boy ∝ (Weight of first boy / Weight of second boy) × (Time taken by second boy / Time taken by first…
Correct answer: 16/25