A body of mass 10 kg is acted upon by a force given by equation ` F=(3t^(2)-30)` Newtons. The initial velocity of the body is 10 m/s. The velocity of the body after 5 secs. is

Options

A. 4.5m//s
B. 6m//s
C. 7.5m//s
D. 5m//s

Answer

c

Explanation

`m[v-u]= int Fdt`
`int(3t^(2)-30)dt`
`3t^(3)/3-t=t^(3)-30 t`
At=5s,
`m[v-u]=(5)^(3)-30(5)=-25`
10[v-10]=-25
v=7.5m//s