a bullet of mass 10 g is fired from a rifle with a velocity of 800 m/s . after passing through a mud wall 180cm thick, the velocity drops to 100m/s. calculate the average resistance of the wall.
mass of the bullet = 10 g or 0.01 kg
Initial velocity = 800 m/s
Final velocity = 100m/s.
thickness of the mud wall, s = 180cm or 1.8 m
Now from the Newton's third equation of motion we can calculate the retardation caused in the bullet because of mud wall
2as = v2 – u2
a = -175000 m/s2
Average resistance of the wall = ma = 1750N and will act against the motion of the bullet.