Question

Two masses m and M (>m) are joined by a light string passing over a smooth light pulley. The centre of mass of the system moves with an acceleration –

• A. g$\left( \frac{M–m}{M + m} \right)$ downward
• B. g$\left( \frac{M–m}{M + m} \right)^{2}$ downward
• C. g$\left( \frac{M–m}{M + m} \right)^{2}$ upward if M < m
• D. Zero

Answer 1

Answer: (B)

g$\left( \frac{M–m}{M + m} \right)^{2}$ downward

Answer 2

a = $\frac{(M–m)g}{M + m}$, a_cm = $\frac{Ma + ma}{M + m}$