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 23 of 38
- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Gain in K.E = Work done View the attached image.
Correct answer: Option B- A. 3.2 kW
- B. 32 kW
- C. 5 kW
- D. 50 kW
Explanation: Energy of motor = Gain in gravitational P.E80%W = mgh0.8(Pt) = mgh0.8P(120) = (400)(10)(1200)P = (400)(10)(1200) / (0.8)(120)=40000 / 0.8…
Correct answer: 50 kW- A. Change in its K.E always
- B. Change in its K.E and change in its P.E
- C. Change in its P.E always
- D. neither change in K.E nor change in its P.E
Explanation: By work energy principle:"Work done on a body equals the change in its kinetic energy and change in potential energy of the body."Work…
Correct answer: Change in its K.E and change in its P.E- A. 36 x 10^6J
- B. 36 x 10^9J
- C. 36 x 10^12J
- D. 36 x 10^8J
Explanation: 1MWh = 10^6 x 3600 watt s 1MWh = 36 x 108 J
Correct answer: 36 x 10^8J- A. Less than its energy at A
- B. Greater than its energy at A
- C. Equal to its energy at A
- D. Zero
Explanation: Ea = Eb = Ec = mgh (by conservation of energy). Therefore, the correct answer is option C: The energy of the body at the point "C" (ground…
Correct answer: Equal to its energy at A- A. 3000 J
- B. 600 watt
- C. 3000 J sec-1
- D. 60 kilowatt
Explanation: h (15)(40) cm = 600 cm = 6m W = mg = 500N P= mgh/t => (500)(6)/5 => 600 watt
Correct answer: 600 watt- A. 0 J
- B. 2 J
- C. 1 J
- D. 4 J
Explanation: W = F .d W = Fcd cos0 = Fcd cos90o = Fd (0) = 0 Due to centripetal force the object will move in a circular path. In the circular path.
Correct answer: 0 J- A. Zero
- B. 4 units
- C. 8 units
- D. 2 units
Explanation: Work done = Area under F-d graph =1/2 (2)(4) = 4 units
Correct answer: 4 units- A. 10%
- B. 50%
- C. 100%
- D. 21%
Explanation: Explanation has been given below. View the attached image.
Correct answer: 21%- A. 8 J
- B. 80 J
- C. 160 J
- D. 4 J
Explanation: According to work energy principle Acquired K.E = Work done = Fd = (4)(2) = 8 J
Correct answer: 8 J- A. 72 J
- B. 48 J
- C. 120 J
- D. 192 J
Explanation: By conservation of linear momentum Total initial momentum= Total final momentum 0 = m1v1 + m2v2 0 = (6)v1+ (4)(12) v1 = -48 / 6 -8 m/s…
Correct answer: 192 J- A. 1:1
- B. 1:2
- C. 2:1
- D. 4:1
Explanation: Let the Kinetic energy of 1kg body be K.E1 and 2kg body be K.E2 K.E = 1/2 mv2 can also be written (m2v2)/2m P = mv m2v2 = p2 K.E = P2 / 2m…
Correct answer: 2:1- A. 500 watt
- B. 1000 watt
- C. 1250 watt
- D. 2000 watt
Explanation: Power = work done / time Weight of the block = mg = 250 x 10 = 2500 N Work done = F x d = 2500 x 2 = 5000 J Power = 5000 / 2.5 = 2000 W
Correct answer: 2000 watt- A. Kinetic energy
- B. Momentum
- C. Acceleration
- D. Potential energy
Explanation: In free fall, the acceleration is equal to the gravitational acceleration.
Correct answer: Acceleration- A. √2gh
- B. √gh
- C. √gh/2
- D. 2√gh
Explanation: Loss in potential energy = Gain in Kinetic energy Initial P.E = mgh P.E after half of this energy is lost = mgh/2 K.E = P.E 1/2 mv2 =…
Correct answer: √gh- A. 103J
- B. 105J
- C. 3.6 x 10^5J
- D. 3.5 x 10^6J
Explanation: Power = work done / time Work done = power x time Power = 1kW = 1000 W = 1000 x 1 = 1000 J = 103J
Correct answer: 103J- A. E
- B. E/2
- C. E√2
- D. Zero
Explanation: The velocity at the highest point is given by the horizontal component, as the vertical component is zero.
Correct answer: E/2- A. 0.5 F
- B. 0.866F
- C. Fcos30o
- D. 0.707 F
Explanation: The effective component of force is that which is in the direction of displacement.
Correct answer: 0.5 F- A. Proton
- B. Electron
- C. Neutron
- D. α-particle
Explanation: First, write the equation of kinetic energy in terms of momentum. K.E = 1/2 mv2 = m2v2/2m = P2/2m as p=mv so, p2 = m2v2 K.E = P2/2m the…
Correct answer: Electron- A. 400 J
- B. 3920 J
- C. 2800 J
- D. 4000 J
Explanation: By law of conservation of energy Gain in K.E = Loss in P.E So, the maximum potential energy is equal to the maximum kinetic just before it…
Correct answer: 400 J