Question

A bullet moving with a velocity of 2m/s penetrates a wooden block and comes to rest after traversing 4 cm inside it. What is the retardation ?

Answer 1

Answer:

u=2m/s and v=0 s=.04m  so retardation a=2su2−v2=50m/s2

to travel a distance s=0.09m in the same block the velocity needed u will be given by v2=u2−2as

 or u=(2as+0)=2×50×.09=3m/s=300cm/s

Answer 2

u= 2m/s and v = 0 s=0.4 m so

.....retardation a = 2s2-v2=50 m/s2

to travel a distance s = 0.009 m in the same block the velocity needed u will be given by v2=u2-2as

or u = ( 2as+0)=2*50*0.9=3m/s=300cm/s