STANDARDPhysics-Work, Energy and Power

STANDARD Physics Kinetic Energy MCQ Question

Type: MCQ-numerical-Medium-Class 11

In a ballistics demonstration a police officer fires a bullet of mass 50 g with speed 200 m s⁻¹ on soft plywood of thickness 2 cm. The bullet emerges with only 10% of its initial kinetic energy. The emergent speed of the bullet is

A

2√10 ms⁻¹

B

20√10 ms⁻¹

C

10√2 ms⁻¹

D

10√20 ms⁻¹

Correct Answer

Option B

Detailed Explanation

The initial kinetic energy of the bullet is 1000 J. Since the bullet emerges with only 10% of its initial kinetic energy, the final kinetic energy is 100 J. Using the formula for kinetic energy, we can solve for the emergent speed, vₑ = √(2Kₑ/m) = 20√10 ms⁻¹.

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