A body of mass 2 kg is moving with velocity 5 m/s. Its kinetic energy is MCQ with Answer and Explanation

A body of mass 2 kg is moving with velocity 5 m/s. Its kinetic energy is
A. 50 J
B. 10 J
C. 25 J
D. 5 J
Answer: Option C
Solution (By JKExamLibrary)
K.E. = ½ m v² = ½ × 2 × 5² = 1 × 25 = 25 J. Use formula correctly. If velocity doubled, KE quadrupled. Unit joule.

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Practice More Physics Questions

Question #1
Three 3Ω resistors in parallel: equivalent resistance is:
A. 0.33Ω
B.
C.
D.

Correct Answer: Option B


Explanation:
1/R_eq = 1/3 + 1/3 + 1/3 = 1 ⇒ R_eq = 1Ω. For n equal resistors in parallel: R_eq = R/n. Memory tip: 'Parallel: reciprocal sum; result < smallest resistor'. Basic circuit calculation frequently tested in competitive exams to verify parallel combination formula.

This question belongs to: Science Physics
Question #2
An object moving with uniform circular motion has
A. Constant acceleration
B. Constant velocity
C. Constant displacement
D. Constant speed

Correct Answer: Option D


Explanation:
Speed constant, velocity and acceleration (centripetal) change direction. KE constant.

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Question #3
The speed of sound in air at 0°C is approximately 332 m/s. At 27°C, it will be approximately:
A. 350 m/s
B. 332 m/s
C. 360 m/s
D. 340 m/s

Correct Answer: Option A


Explanation:
Speed of sound in air v ∝ √T, where T is absolute temperature in Kelvin. T₀ = 0°C = 273 K, v₀ = 332 m/s. T = 27°C = 300 K. Thus v = v₀√(T/T₀) = 332 × √(300/273) ≈ 332 × √1.099 ≈ 332 × 1.048 ≈ 348 m/s ≈ 350 m/s. Approximate rule: speed increases by 0.6 m/s per °C rise, so 27×0.6≈16.2, 332+16.2≈348.2 m/s. Memory aid: 'v ∝ √T in Kelvin'. Such temperature-dependence problems test application of sound wave properties, common in competitive exams with emphasis on absolute temperature usage.

This question belongs to: Science Physics