A man is riding on a cycle with velocity `7.2(km)/(hr)` up a hill having a slope 1 in 20. The total mass of the man and cycle is 100kg. The power of the man is

Options

A. 200 W
B. 175 W
C. 125 W
D. 98 W

Answer

D

Explanation

`v= 7.2 (km)/(h)= 7.2 xx (5)/(18) =2m//s`
Slope is given 1 in 20
`therefore sin theta= (1)/(20)`

When man and cycle moves up then component of weigth opposes it motion i.e. `F= mg sin theta`
So power of the man `P= F xx v= mg sin theta xx v`
`=100 xx 9.8 xx ((1)/(20))xx 2= 98` Watt