A 3-kg steel ball strikes a wall with a speed of `10.0ms^(-1)` at an angle of `60.0^(@)` with the surfaces of the wall. The ball bounces off with the same speed and same angle. If the ball was in contact with the wall for 0.2s, find the average force exerted by the wall on the ball.

Options

A. `300 N`
B. zero
C. `150 sqrt(3) N`
D. `150N`

Answer

D

Explanation

As is clear from figure , components of momentum perpendicular to wall cancel out, and components along the wall add. As
`Fxxt=` change in momentum
`=2 m upsilon cos theta`
`:. F=(2 m upsilon cos theta)/( t)=(2xx3xx10cos 60^(@))/( 0.2)`
`(60)/(2)xx(10)/(2)=150N`