A gun which fires small balls of mass `20 g` is firing `20 balls` per second on the smooth horizontal table surface `ABCD`. If the collision is perfectly elastic and balls are striking at the centre of table with a speed of `5 m//s` at an angle of `60^(@)` with the vertical just before collision, then force exerted by one of the legs on ground is (assume total weight of the table is `0.2 kg`)

Options

A. `0.5 N`
B. `1 N`
C. `0.25 N`
D. `0.75 N`

Answer

B

Explanation

Force exerted by one leg on the ground
`N = (1)/(4) xx ["Total force"]`
`= (1)/(4) ["wt + rate of change of momentum"]`
`= (1)/(4) [Mg + n(mv cos 60^(@)) xx 2] = 1N`