A body of mass 10kg is being acted upon by a force `3t^2` and an opposing constant forces of 32N. The initi speed is 10ms. The velocity of body after 5s is

Options

A. `14.5ms^(-1)`
B. `6.5ms^(-1)`
C. `3.5ms^(-1)`
D. `4.5ms^(-1)`

Answer

B

Explanation

`F=3t^2-32, " " a=F/m =(0.3t^2-3.2)`
`int_(10)^v dv= int_0^5 adt = int_0^5 (0.3t^2-3.2)dt, v-10=3.5 :. v=6.5m//s`