A bullet with a velocity of 100 m/s can just penetrate 2 planks of equal thickness. What is the number of planks penetrated if the velocity of the bullet is doubled?
Correct answer: C. 8
- A. 4
- B. 6
- C. 8
- D. 10
Explanation
Penetration relates to the kinetic energy available to do work against the planks. Kinetic energy scales with the square of velocity, so doubling v increases K.E by 4 times. Therefore the bullet can penetrate 4 × 2 = 8 planks, neglecting non‑ideal losses.
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