A cricket ball of mass `150g` has an initial velocity `(3 hati + 4hatj)ms^(-1)` and a final velocity `upsilon = -(3hati + 4hatj)ms^(-1)` after beigh hit The change in momentum (final momentum initial momentum) is (in kg `ms^(-1)`)

Options

A. zero
B. `-(0.45hati +0.6 hatj)`
C. `-(0.9 hatj +1.2 hatj)`
D. `-5(hati +hatj)hati`

Answer

C

Explanation

Given `u = (3 hati + 4hatj)m//s`
and `v = - (3hati +4hatj) m//s`
mass of the ball `=150 g = 0.15 kg`
`DeltaP = mv -"mu"`
`DeltaP =m(v -u) = - (0.15) [(3hati + 4hatj)-(3hati + 4hatj)]`
`= (0.15) [-6hati -8hatj]`
Hence `Deltap = - [0.9hati + 1.2hatj]` .