Two bodies of mass 4 kg and 5 kg are moving along East and North directions with velocities 5 m//s and 3 m//s respectively. Magnitude of the velocity of centre of mass of the system is

Options

A. `25/9m//s`
B. `9/25m//s`
C. `41/9m//s`
D. `16/9m//s`

Answer

a

Explanation

Velocity of centre of mass = `(m1 v1+m2 v2)/(m1+m2) `
`V=(4xx5hati+5xx3hatj)/(5+4)=20hati/9+15hatj/9`
therfore Magnitude,|V|=`sqrt([(20)/(9)]^(2)+[(15)/(9)]^(2))`
`25/9 m//s`