A cricket ball of mass `150g` moving with a speed of `126km//h` hits at the middle of the bat, held firmly at its position by the batman. The ball moves straight back to the bowler after hitting the bat. Assuming that collision between ball and bat is completely elastic and the two remain in contact for `0.001s`, the force that the batsman had to apply to hold the bat firmly at its place would be

Options

A. 10.5 N
B. 21 N
C. `1.05 xx10^(4)`N
D. `2.1 xx10^(4) N `

Answer

C

Explanation

Given m = 150 g = 0.15 kg , `v = 126 xx5/18 = 36 ms^(-1)`
Since Impulse = change in momentum
` F xx t = m (v - u)`
`F xx 0.001 = 0.15 (-35 -35)`
or `F = - 1.05 xx10^(4) N `
Negative sign means that the force applied in a direction opposite to the direction of motion of the ball .