A 0.04 kg bullet moving at 90 m s⁻¹ is stopped after penetrating 0.6 m into a block. The average resistive force is:
A3.6 N
B540 N
C120 N
D270 N
Answer & Solution
Correct answer: D. 270 N
Retardation a = u²/2s = 90²/(2×0.6) = 6750 m s⁻²; resistive force F = ma = 0.04×6750 = 270 N (average).
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