A bullet of mass 0.015kg strikes a metal plate of the thickness 10cm with velocity 400m/s and emerge from it with 260m/s. Find average resistance offered by the metal plate to motion of the bullet.
m = 0.015 kg
u = 400m/s
v = 260 m/s
s=thickness =10 cm=0.1 m
v^2−u^2 = 2as
67600-160000 = 0.2a
a = −462000 m/s^2
Resistance offered = resistive force = ma = 0.015×-462000 = -6930 N
Sign is negative because it is opposite to the motion of the bullet.
Hence the magnitude of resistive force is 6930 N