In a second ODI match between England and India Bhuwnesh kumar bowled his medium fast bowling. He starts his run up from the distance of `50m` from the stumps (bowling end) and at the time of bowling a ball,his speed is `36(km)//(hr)` and the speed of ball is `144(km)//(hr)`.
If his mass is `70 kg` and mass of the ball is `(1)/(4)kg` and the heat produce in his body is one tenth of the total work done by him, then
If he accelerates uniformly to the sumps find the average friction force acting on him `:-`

Options

A. `750` N
B. `70.25` N
C. `90.25` N
D. `70` N

Answer

B

Explanation

By using `V^(2)=u^(2)+2as` we have
`(36xx(5)/(18))^(2)=0^(2)+2xxaxx50rArra=1 m//s^(2)`
`:. F=mxxa=(70xx(1)/(4))xx1N=70.25N`