Question

A bullet is target with velocity 80 m/s and penetrate 50 cm into it. If this bullet were fired into a target 25 cm thick with equal velocity with what velocity would it emerge supposing the resistance to the uniform and same for both cases?

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Answer 1

First, calculate the deceleration caused by 'it' on the bullet.

v² = u² + 2×a×s
0² = 80² + 2×a×0.5
a = -6400 m/s²

Now you can find final velocity of the bullet when emerging 'it'
v² = 80² + 2×(-6400)×0.25
v = 1.4 m/s