Question

a bullet initially moving with a velocity 20 m/s strikes a target and comes to rest after penetrating a distance 10 cm in the target calculate the retardation caused by the target

Answer 1

u=20m/s
a=?
v=0
d=10cm=0.1m
2as=v2-u2
2*0.1*a=0(square)-400
0.2a=400
a=400/0.2
a= -2000m/s