Question

if a body loses half of its velocity on penetrating 3 cm in a wooden block then how much will it penetrate more before coming to rest
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Answer 1

Answer: 1 cm

Explanation:

by equation of motion,

v^2= u^2 +2as

(v/2)^2= v^2 +2as

v^2/4 -v^2= 2as

2as= -3v^2/4

a= -3v^2/4×2s

a= -3v^2/24

a= -v^2/8

Now,

v^2= u^2 + 2as

And the final velocity is zero

0= v^2/4 -2×(v^2/8)×s

s= (v^2/4)/2× v^2/8

So,

s= 1cm