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 3 of 38
- A. momentum increases 4 times and K.E increases 2 times
- B. momentum and K.E. remain same
- C. momentum increases 2 times and K.E increases constant
- D. momentum increases 2 times and K.E increases 4 time
Explanation: Momentum is p = mv, so doubling velocity doubles momentum. Kinetic energy is K.E.
Correct answer: momentum increases 2 times and K.E increases 4 time- A. Proton
- B. electron
- C. neutron
- D. a-particle
Explanation: For equal momentum, kinetic energy is K.E. = p²/(2m), so the particle with the smallest mass has the greatest kinetic energy.
Correct answer: electron- A. 6ge
- B. ge/6
- C. 2ge
- D. Zero
Explanation: The Moon's gravitational acceleration is approximately one-sixth of Earth's: gmoon ≈ 9.8 m/s^2 ÷ 6 ≈ 1.63 m/s^2 = ge/6.
Correct answer: ge/6- A. 0.125 J
- B. 0.250 J
- C. 0.50 J
- D. 1 J
Explanation: For a linearly stretched wire, the stored elastic energy is the area under the force-extension graph: E = 1/2 F x = 1/2 x 100 N x 0.005 m…
Correct answer: 0.250 J- A. 7.2 m/s²
- B. 1.62 m/s²
- C. 9.8 m/s²
- D. 3.75 m/s²Calculators & Reference Tools
Explanation: The Moon's gravitational acceleration at its surface is approximately 1.62 m/s², about one-sixth of Earth's 9.8 m/s².
Correct answer: 1.62 m/s²- A. 274 m/s²
- B. 362 m/s²
- C. 300 m/s²
- D. None of these
Explanation: The gravitational acceleration at the Sun's surface is approximately 274 m/s², found from g = GM/R².
Correct answer: 274 m/s²- A. x = x'
- B. x = x'/2
- C. x = x'/4
- D. x = x(2)'/2
Explanation: In SHM, potential energy is PE = 1/2 kx², while its maximum value occurs at displacement x'.
Correct answer: x = x'/2- A. material objects only
- B. material objects and electromagnetic radiation only
- C. electromagnetic radiations
- D. none of the above
Explanation: In Einstein's relativity, electromagnetic radiation carries energy and momentum, so it participates in gravitational interaction along…
Correct answer: material objects and electromagnetic radiation only- A. 0.01J
- B. 0.02J
- C. 0.04J
- D. 1.0J
Explanation: The wire's elastic energy is the area under its linear force-extension graph: E = 1/2 x F x x = 1/2 x 20 N x 0.001 m = 0.010 J.
Correct answer: 0.01J- A. FE
- B. (FE)
- C. FE2/L
- D. FE2
Explanation: For a linearly elastic wire, the stored energy equals the triangular area under the force-extension graph: E = 1/2 x F x E, in joules when…
Correct answer: (FE)- A. Earth
- B. Neptune
- C. Jupiter
- D. Moon
Explanation: Escape velocity is vesc = √(2GM/R), so it is greatest for a body with a large mass and relatively small radius.
Correct answer: Jupiter- A. once
- B. twice
- C. four time
- D. eight time
Explanation: At most coastlines, the Moon's tidal effect produces two high tides and two low tides during approximately one lunar day, about 24.8 h.
Correct answer: twice- A. heat energy to K.E
- B. elastic P.E to K.E
- C. elemical energy to elastic P.E
- D. K.E to elastic P.E.
Explanation: The stretched bow stores elastic potential energy, which changes mainly into the arrow's kinetic energy when the string is released.
Correct answer: elastic P.E to K.E- A. decay of radioactive element in the earth
- B. compression of material in the earth
- C. residual lost of the earth
- D. all as said in A - B and C
Explanation: Geothermal energy comes from heat inside Earth, including heat released by radioactive decay, residual heat from Earth's formation, and…
Correct answer: all as said in A - B and C55. The escape velocity of a body in gravitational field of earth is independent of__________________?
- A. its mass
- B. the angle at which it is thrown
- C. both its mass and the angle at which it is thrown
- D. gravitational field of earth
Explanation: Escape velocity is v = √(2GM/R), so it depends on the planet's mass and radius, not on the mass of the escaping body.
Correct answer: both its mass and the angle at which it is thrown- A. 38.2 J
- B. 392.1 J
- C. 39.2 J
- D. 3.92 J
Explanation: The work done in raising the body equals its gain in gravitational potential energy: W = mgh = 2 kg x 9.8 m s-2 x 2 m = 39.2 J.
Correct answer: 39.2 J- A. watt
- B. Joule
- C. Newton
- D. Pascal
Explanation: Power is the rate of doing work or transferring energy, P = W/t, and its SI unit is the watt (W).
Correct answer: watt- A. Force and time
- B. Force and velocity
- C. Force and speed
- D. None of these
Explanation: Mechanical power is the rate of doing work: P = F · v = Fv cosθ, so it is the dot product of force and velocity.
Correct answer: Force and velocity- A. displacement
- B. acceleration
- C. power
- D. energy
Explanation: Power is the rate at which work is done, P = W/t. Therefore, the slope of a work-time graph, ΔW/Δt, is power and is measured in watts.
Correct answer: power- A. 1 hp = 546 watts
- B. 1 hp = 746 watts
- C. 1 hp = 1000 watts
- D. 1 hp = 946 watts
Explanation: The mechanical horsepower is defined as approximately 746 W. Thus 1 hp = 746 watts, where a watt is 1 J/s.
Correct answer: 1 hp = 746 watts