Physics

Problem

A rifle of mass

4\,\text{kg}

fires a

20\,\text{g}

bullet that starts from rest inside the barrel. The force acting on the bullet while it is in the barrel (for

0 \le t \le 2.0\,\text{ms}

) is

F(t)=6.0\times10^{6} t - 1.5\times10^{9} t^{2}

(SI units). After the bullet leaves the barrel, find the recoil speed of the rifle. a)

4.0\,\text{m s}^{-1}

backward b)

2.0\,\text{m s}^{-1}

forward c)

2.0\,\text{m s}^{-1}

backward d)

1.0\,\text{m s}^{-1}

backward