A bird of 3 kg is flying with a constant velocity of `(2hati-4hatj)m//s` and another bird of 2 kg with `(2hati+6hatj)m//s`. Then, the velocity of centre of mass of the system of two bird ……….. Is m/s.

Options

A. `10hati+10hatj`
B. `2hati+2hatj`
C. `2hati-2hatj`
D. `2hati+0hatj`

Answer

D

Explanation

`vecv_(cm)=(m_(1)vec(v_(1))+m_(2)vec(v_(2)))/(m_(1)+m_(2))`
`=(3(2hati-4hatj)+2(2hati+6hatj))/(2+3)`
`=(6hati-12hatj+4hati+12hatj)/(5)`
`=(10hati+0hatj)/(5)`
`=2hati+0hatj`