Free Work and Energy MCQs with Answers

• A. √2
• B. 2
• C. 4
• D. 8

Explanation: K.E = 1/2 mv2 Since mass is constant K.E ∝ v2 v' = 2 v K.E' ∝ (2v)2 K.E' ∝ 4 v2 K.E' / K.E = 4v2 / v2 = 4 K.E' = 4 K.E ==> K.E increases…

• A. 746 W
• B. 746 KW
• C. 746 MW
• D. 746 GW

Explanation: Fact: To convert horse power --> watts = hp x 746 = watts 1 hp = 1 x 746 = 746 W

• A. √m1 : √m2
• B. m1 : m2
• C. m2 : m1
• D. √m12 : √m22

Explanation: The kinetic energy of a body is given by the formula: E = 1/2mv^2 where: E is the kinetic energy m is the mass of the body v is the…

• A. Winds
• B. Gravity
• C. Clouds
• D. The rotation of earth

Explanation: The atmosphere is held to the Earth by gravity. The Earth's gravity pulls on the atmosphere, which is why it doesn't float away into…

• A. 44%
• B. 55%
• C. 66%
• D. 77%

Explanation: Option A is correct according to the following calculations. The increase in kinetic energy is 44%.

• A. 2.8 J
• B. 3.2 J
• C. 3.8 J
• D. 4.4 J

Explanation: Option D is correct as the increase in kinetic energy is given by the following formula: ΔKE = 1/2mv2f - 1/2mv2i = 1/2 * 5 * 4.4^2 - 1/2 *…

• A. Double
• B. 4 times
• C. Half
• D. 1/4 times

Explanation: The work done by a force is given by the formula: Work = Force * Displacement If the force and displacement are doubled, then the work…

• A. I = 3λ/4
• B. I = λ/2
• C. I = 3λ/2
• D. I = 2λ/3

Explanation: Option C is correct as λn = 2L/n n =3 λn =2L/3 3λ/2=L

• A. Increase in the velocity of sound
• B. Decrease in the velocity of sound
• C. Increase in frequency of sound
• D. Increase in both velocity and frequency of sound

Explanation: Option C is correct fA = (v/v - us) f fA > f So frequency will increase and wavelength will decrease

• A. 60 cm
• B. 40 cm
• C. 120 cm
• D. 80 cm

Explanation: From figure, the length of 2nd resonance position is 3 times of the length of 1st resonance position so the correct answer is 150cm

• A. 1024
• B. 512
• C. 256
• D. 128

Explanation: Fundamental frequency of a closed pipe, f= v/4L = 512 Hz

• A. 118 W
• B. 130 W
• C. 146 W
• D. 193 W

Explanation: Determine Total Height and Mass of Water: The total height (H) the water needs to be lifted is the sum of the height of the tank above…

• A. P = dE/dv
• B. P = dE/dt
• C. P = dv/dt
• D. P = (dE/dv) (dE/dt)

Explanation: If v, P and E denote the velocity, momentum and kinetic energy of a particle then:P = dE / dv

• A. Work done is proportional to velocity squared
• B. Work done is equal to the product of force and time
• C. Work done is directly related to the integral of K/V over time
• D. Work done is constant regardless of the particle's velocity

Explanation: The correct answer is Option C. The force acting on the particle is given by F = K/V, indicating that the force decreases as velocity…

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: F→ = F · f→ = 30 ( (i→ + j →+ k→) / √3 )F→ = 10√3 ( i→ + j→ + k→ )and S→ = r₂→ - r₁→ = 2 i→ + k→∴ W = F→ · S→ = 30√3 J

• A. 5 m/s
• B. 14 m/s
• C. 17.5 m/s
• D. 10 m/s

Explanation: F = − [ (ΔU / Δx) î + (ΔU / Δy) ĵ ] = − [7 î + 24 ĵ] F = √(7² + 24²) = 25 N ⇒ a = F / m = 25 / 5 = 5 m/s² v = u + at = 0 + 5 × 2 = 10 m/s

• A. U/N
• B. NU
• C. N2U
• D. U /N3

Explanation: Understanding the ConceptsPotential Energy of a Spring: The potential energy (PE) stored in a spring is given by:PE=1/2kx²Where:PE is the…

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: As the particle moves in a circle mv²/r = k/r² ∴ K.E. = 1/2 mv² = k/2rNow potential energy U = - ∫ F dr = - k/r∴ total energy = - k/2r

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: mu = mv1 + mv2 ⇒ u = v1 + v2e = (v2 - v1) / (u1 - u2) ⇒ e = (v2 - v1) / (u = 0) ⇒ v2 - v1 = eu∴ v2 / v1 = (1 - e) / (1 + e)

• A. 3.6 JK
• B. 3.6 J
• C. 3.6 MJ
• D. 3.6 GJ

Explanation: Solution:- Mega watt hour is related with joule as:1MWh =1 x 10^6 x 3600 Ws=3.6 x 10^9 J1MWh = 3.6 GJ