A riding ball of mass `m` strikes a rigid wall at `60^(@)` and gets reflected without loss of speed as shown in the figure below. The value of impulse imparted by the wall on the ball will be.

Options

A. `(mV)/(2)`
B. `(mV)/(3)`
C. `mV`
D. `2mV`

Answer

C

Explanation

`vec(DeltaV)=vec(V)_(f)-vec(f)_(i)`
`=(-Vcos60^(@)hati-Vsin60^(@)hatj)`
`-(Vcos60^(@)hati-Vsin60^(@)hatj)`
`vec(DeltaV)=-2Vcos60^(@)hati`
Impulse
`I=|vec(DeltaP)|=m|DeltaV|=m(2Vcos60^(@))=mV` .