Question

System shown in figure is in equilibrium and at rest. The spring and strings are massless. Now the string between B and C is cut. Choose the correct option(s) just after cut. (g = 10 $m{s}^{-2}$)

• A. acceleration of A is zero
• B. acceleration of B is g in upward direction
• C. acceleration of C is g in downward direction
• D. none of these

Answer 1

The correct option is B acceleration of B is g in upward direction

Initially under equilibrium of mass m,

$T=mg$

Now, the string is cut. Therefore, T = mg force is decreased on mass m upwards and downwards on mass 2m.

$a_m=\frac{mg}{m}=g$

$a_{2m}=\frac{mg}{2m}=\frac{g}{2}$