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 27 of 38
- A. 2 x 10^3J
- B. 103J
- C. 104J
- D. 4 x 10^4 J
Explanation: Correct.Change in K.E = 1/2 mv²W= 1/2 50×20^2W= 10000J
Correct answer: 104J- A. 6 MW
- B. 1.025 MW
- C. 5 MW
- D. 2.05 MW
Explanation: The power of the engine is determined by the work done over time. First, calculate the change in kinetic energy, which is given by:ΔKE =…
Correct answer: 2.05 MW- A. √2
- B. 2
- C. 4
- D. 16
Explanation: Formula:KE1/KE2= p1/p2²m2/m1 Calculation:KE1/KE2 =( 2/1)^2 ×{4/1} = 4 ×4 = 16 The ratio of kinetic energies is 16:1.
Correct answer: 16524. A particle of mass m at rest is acted upon by a force F for a time t. Its K.E after an interval t is
- A. F²t²m
- B. F²t²/3m
- C. F²t2/2m
- D. Ft/2m
Explanation: Since the particle is initially at rest, its initial velocity is 0. Using the equation v = u + at (where u is the initial velocity), we…
Correct answer: F²t2/2m- A. Unchanged
- B. Doubled
- C. Halved
- D. Four times
Explanation: K.E = 1/2 mv^2(K.E)' = 1/2 (m/2) (2v)^2 = 1/2 (m/2) 4v^2 = 2 (1/2 mv^2) = 2 (K.E)
Correct answer: Doubled- A. Zero
- B. 2.5 cm
- C. 5 cm
- D. 1.25 cm
Explanation: Initially mass 10 gm moves with velocity 100cm/s∴ Initial momentum = 10 × 100 = 1000 gm × cm/secAfter collision system moves with velocity…
Correct answer: 1.25 cm- A. 2 times
- B. 5 times
- C. 4 times
- D. 16 times
Explanation: Mass is indrectly proportional to KE. Doubling the mass will give double KE.
Correct answer: 2 times- A. 250 J
- B. 2500 J
- C. 125 J
- D. 10000 J
Explanation: K.E = (1/2)mv^2= (1/2)(0.5)(200)^2 = (1/2)(0.5)(40000)= (1/2)(20000) = 10000 J
Correct answer: 10000 J- A. 6:1
- B. 1:1
- C. 36:1
- D. 1:6
Explanation: (K.E)E / (K.E)M = (1/2 mv²) / (1/2 mv²) = 1 : 1(For same mass and speed)
Correct answer: 1:1- A. The velocity of the object
- B. The kinetic energy of the object
- C. The mass of the object times its velocity
- D. The weight of the body
Explanation: The correct answer is Option B: The kinetic energy of the object. According to the work-energy principle, the work done on an object to…
Correct answer: The kinetic energy of the object- A. 40 J
- B. 160 J
- C. 90 J
- D. 400 J
Explanation: By work energy principleWork done = Change in kinetic energyWork = (1/2) m vf² - (1/2) m vi² = (1/2) m ( vf² - vi²)= (1/2)(5)(10² - 6²) =…
Correct answer: 160 J- A. 6 J
- B. 12 J
- C. 8 J
- D. 18 J
Explanation: Work = 1/2 m (vf² - vi²)= 1/2 (4) (0² - 3²) = (2) (-9) = -18 J-ve sign indicates that the loss in K.E which is converted into P.E.
Correct answer: 18 J- A. 14000 √3 m/sec
- B. 20 sin 30o m/sec
- C. 1.4 m/sec
- D. 14 m/sec
Explanation: h/20=sin 30o => h=20sin30o = 20(0.5) =10mBy law of conservation of energyGain in K.E = Loss in Gravitational P.E1/2mv2 = mghv2 = 2ghv2 =…
Correct answer: 14 m/sec- A. 8 hp
- B. 15 hp
- C. 25 hp
- D. 16 hp
Explanation: P = (2400)(10)(74.6) / 300 watt = (2400)(10)(74.6) / (300)(746) hp= 8 hp (1 hp = 746 watt)
Correct answer: 8 hp- A. 10%
- B. 50%
- C. 100%
- D. 20%
Explanation: The relationship between kinetic energy (K.E) and linear momentum (p) is given by the formula K.E = p²/2m.
Correct answer: 20%- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: This option is correct according to formula of average power isP= mv²/2t
Correct answer: Option C- A. K.EA = K.EB
- B. K.EA = 1/2 K.EB
- C. K.EA = 2K.EB
- D. K.EA = 4K.EB
Explanation: Given:Object A has half the mass of object B.The two objects have equal momentum.Known:Momentum, p = mvKinetic energy, KE =…
Correct answer: K.EA = 2K.EB- A. 2
- B. -2
- C. 1/2
- D. 1
Explanation: We use the formula, W = F.d0 = (6i + 2j - 3k)(2i -3j+xk)x = 12 - 6 -3x3x = 6x = 2
Correct answer: 2- A. 50 J
- B. 100 J
- C. 150 J
- D. 160 J
Explanation: We use the formula,W=F.d = (−2i+15j+6k)(10j) = (15)(10) = 150Hence, this is the correct option.
Correct answer: 150 J- A. 6 J
- B. 10 J
- C. 12 J
- D. 8 J
Explanation: To find the total work done when a force is applied at an angle, we use the formula W = Fdcosθ.
Correct answer: 10 J