The velocities of three particles of masses 20 g, 30 g and 50 g are `10hat`i, `10hatj` and `10hatk` respectively. The velocity of the centre of mass of the three particles is

Options

A. `2hati+3hatj+5hatk`
B. `10(hati+hatj+hatk)`
C. `20hati+30hatj+5hatk`
D. `2hati+30hatj+50hatk`

Answer

(a)

Explanation

`V_(cm)=(m_(1)v_(1)+m_(2)v_(2)+m_(3)v_(3))/(m_(1)+m_(2)+m_(3))`
rArr `V_(cm)=((20xx10hati)+(30xx10hatj)+(50xx10hatk))/(20+30+50)`
because ` V_(cm)=(200hati+300ghatj+500hatk)/(100)=2hati+3hatj+5hatk`