Question

Two particles of masses 2m & m tied to string as shown. Particel of mass m is released from given position. Impulse provided by string to particle of mass 2m at the instant when 2m losses contact with surface :-

• A. $\frac{4m\sqrt{gl}}{3}$
• B. $\frac{2m\sqrt{gl}}{3}$
• C. $\frac{2m\sqrt{2gl}}{3}$
• D. $\frac{m\sqrt{2gl}}{3}$

Answer 1

Answer: (C)

$\frac{2m\sqrt{2gl}}{3}$

Answer 2

The problem is ill-posed with the given masses and standard physics assumptions. The most plausible path to option (C) is if the velocity of the 2m mass at the instant it loses contact is

$v = \frac{\sqrt{2gl}}{3}$

Impulse $J = \Delta p = (2m)v$ Substitute $v = \frac{\sqrt{2gl}}{3}$:

$J = (2m) \left( \frac{\sqrt{2gl}}{3} \right) = \frac{2m\sqrt{2gl}}{3}$