Question

Two particles one of mass $1$kg and the other of mass $2$kg are projected simultaneously with the same speed from the top of a tower. The particle of mass $1$ kg is projected vertically upward and the particle of mass $2$kg is projected vertically downward. The acceleration of centre of mass is :

• A. $\frac{g}{3}$
• B. $g$
• C. $\frac{g}{2}$
• D. $\frac{g}{4}$

Answer 1

Answer: (B)

$g$

Acceleration of centre of mass, $a_{CM}=\frac{m_1{a}_2+m_2{a}_2}{m_1+m_2}=\frac{g+2g}{1+2}=\frac{3g}{3}=g$.