Question

A 200 g iron ball having velocity 20 m/s collides with a wall normally and rebounds with the same speed. If the period of contact between the ball and wall is 0.05 second, then the force experienced by the wall is (1) 40 N (2) 80N (3)ON (4) 160 N​

Answer 1

m = 0.2Kg u = 20m/s T = 0.05s v = 20m/s

change in momentum =

mu - mv

= 2/20 × 20 - 2/20 × 20

= 2-2 = 0

Impulsive force on the wall by ball = ∆mv/∆t

= 0/0.05

= 0N(zero Newton)