A particle of mass 1 kg is projected upwards with velocity 60 m/s. Another particle of mass 2 kg is just dropped from a certain height. After 2 s when neither of the particles have collided with ground, match the following [Take `g=10m//s^(2)`]

Answer

A, B, C

Explanation

A - Q, B - R, C - R
From `a_(COM) rArr (m _(1)a_(1)+m_(2)a_(2))/(m_(1)+m_(2)) rArr ((1)(-10)+2(-10))/3 rArr -10m//s^(2)`
`U_(COM)=(m_(1)u_(1)+m_(2)u_(2))/(m_(1)+m_(2)) rArr (-(1)(60)+(2)(0))/3=+20m//s`
`s=20 times 2+1/2at^(2)=20 times 2-1/2 times 10 times 4=20m`