Rotational Motion Question 143
Question: A pulley fixed to the ceiling carries a string with blocks of mass m and 3 m attached to its ends. The masses of string and pulley are negligible. When the system is released, its centre of mass moves with what acceleration?
Options:
A) 0
B) $-g/4$
C) $g/2$
D) $-g/2$
Show Answer
Answer:
Correct Answer: C
Solution:
[c] When the system is released, heavier mass move downward and the lighter one upward.
Thus, centre of mass will move towards the heavier mass with acceleration
$a=\left( \frac{3m-m}{3m+m} \right)g=\frac{g}{2}$
