Question

Two particles A and B masses 1 kg and 2 kg respectivelty are projected in the same vertical line as shown in figure with speeds `u_(A) = 200 m//s` and `u_(B) = 85m//s` respectively. Initially they were 90 m apart. Find the maximum height attained by the centre of mass of the system of particles A and B, from the initial position of centre of mass of the system. Assume that none of these particles collides with the ground in that duration Take `g = 10 m//s^(2)`

A. 5 meter
B. 10 meter
C. 25 meter
D. 20 meter

Answer 1

Correct Answer - A
Initially velocity of centre of mass of `(A + B)` system is
`u_(cm)=(1xx200-2 xx85)/(3)=10 m//s` upwards
`:.` maximum height attained by centre of mass above its initial position is
`H=(u_("cm")^(2))/(2g)=(100)/(2xx10)=5` metres