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 20 of 38
- A. 7.2 kilo joules
- B. 720 joules
- C. 120 joules
- D. 72000 joules
Explanation: Power=Energy/time Energy=power ×time 60 watt×120 sec =7200 J =7.2 kilo J.
Correct answer: 7.2 kilo joules- A. 1 J
- B. 2 J
- C. 3 J
- D. 4 J
Explanation: Given:mass(m)=2kg, momentum(p)=2Nswe know; p=mvv=p/m v=1ms-1Kinetic energy (K.E)= 1/2(mv2)K.E=1/2(pv) K.E=1/2x(2x1)K.E=1J
Correct answer: 1 J- A. Joule
- B. Erg
- C. kWh
- D. All of these
Explanation: All of these are units of energy. The most commonly used unit is Joules, however erg is also a unit of energy and it is equal to 10-7…
Correct answer: All of these- A. 3 x 10^21 N s
- B. 9 x 10^-28 N s
- C. 5.4 x 10^-28 Ns
- D. 5.4 x 10^-27 N s
Explanation: Impulse = Change in momentum. The initial momentum mv cf the electron can be resolved into two components.
Correct answer: 5.4 x 10^-28 Ns- A. Mgd/4
- B. 3 Mgd/4
- C. Mgd
- D. -3Mgd / 4
Explanation: Option D is correct as :When the block moves vertically downward with acceleration g/4 the tension in the cord is:T=M(g-g/4)=3Mg/4Work…
Correct answer: -3Mgd / 4- A. TV
- B. TV cosθ
- C. (T cos - mg)V
- D. zero
Explanation: To determine the power delivered by the man, we need to consider the forces acting on the block and the work being done.
Correct answer: TV cosθ- A. 60kg
- B. 100kg
- C. 75kg
- D. 80kg
Explanation: To calculate the amount of water pumped in 5 seconds from a height of 10 meters, we can use the principle of work and energy.
Correct answer: 100kg- A. Total energy
- B. kinetic energy
- C. potential energy
- D. none of these
Explanation: Option C is correct as: The relation between conservative force and potential energy is Fcos = -dU/dx Fcos (dx) = -dU -W = -Fcos (dx) = ∆U
Correct answer: potential energy- A. The tension in the string is Mg.
- B. The tension in the string is F.
- C. The work done by the tension on the block is 20J in 1s.
- D. The work done by the force of gravity is 20J in 1s
Explanation: Option B is correct as the tension in the string is F and not Mg. The work done by all the forces (in this case the tension and the force…
Correct answer: The tension in the string is F.- A. 20 kW
- B. 200 kW
- C. 40 kW
- D. 4 kW
Explanation: To calculate the power of a pump, you can use the formula for power: Power (P) = Work Done (W) / Time (t) In this case, the work done is…
Correct answer: 20 kW- A. Electron volt
- B. Calorie
- C. Joule
- D. All of these
Explanation: Solution:- The different units of energy and their relation with SI-unit is as following:1 kWh = 3.6 MJ1 eV = 1.6 × 10-19 J1 calorie =…
Correct answer: All of these- A. 60°
- B. 30°
- C. 45°
- D. 90°
Explanation: Solution:- W=Fxdcosθ W=Fxdcos(60°) W=1/2 Fxd
Correct answer: 60°- A. 746 J
- B. 746 kWh
- C. 746 W
- D. 746 MWh
Explanation: 1 horse power = 746 W1 kilo watt = 1000 W1 electron volt = 1.6 × 10-19 J
Correct answer: 746 W- A. 10 watt hour
- B. 10 electron volts
- C. Electron volt
- D. Kilo watt hour
Explanation: 10 Wh = 10×3600 Ws = 3.6 ×104 J 10 eV = 10×1.6×10-19 J = 1.6×10-18 J 1 kWh = 3.6×106 J Hence, the correct option for the bigger unit of…
Correct answer: Kilo watt hour- A. 10 J
- B. 100 J
- C. Zero
- D. Infinite
Explanation: Work (W) is defined as the product of force (F) and displacement (d) in the direction of the force.
Correct answer: Zero- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: The product of a particle's mass and velocity is its momentum. The temporal rate of change of momentum is proportional to the force…
Correct answer: Option D- A. 13 J
- B. 26 J
- C. 18 J
- D. 21 J
Explanation: The explanation of this question has been added.
Correct answer: 13 J- A. 1:2
- B. 1:4
- C. 1:1
- D. 4:1
Explanation: Let's assume the two bodies have masses m1 and m2, with kinetic energies K1 and K2, respectively.
Correct answer: 1:4- A. 6 MW
- B. 1.025 MW
- C. 5 MW
- D. 3.4 MW
Explanation: To calculate the power of the engine, we need to use the equation: Power = Force × Velocity First, let's calculate the force applied by…
Correct answer: 3.4 MW- A. 45 W
- B. 90 W
- C. 900 W
- D. 1800 W
Explanation: To calculate the average power, we can use the formula: Average Power = Work / Time First, let's calculate the work done on the box.
Correct answer: 45 W