A force exerts an impulse Ion a particle changing its speed from initial velocity `u` to final velocity `2u`. The applied force and the initial velocity are oppositely oriented along the same line. The work done by the force is

Options

A. `(3)/(2)Iu`
B. `(1)/(2)Iu`
C. I u
D. 2 I u

Answer

B

Explanation

`I=3m u`
`W=DeltaK=(1)/(2)m(2u)^(2)-(1)/(2)m u^(2)=(3m u.u)/(2)=(Iu)/(2)`