Question

Two point masses connected by an ideal string are placed on a smooth horizontal surface as shown in the diagram. A sharp impulse of $10 \, kgms^{- 1}$ is given to the $5 \, kg$ mass at an angle of $60^\circ $ to the line joining the masses. The velocity of the $10 \, kg$ mass just after the impulse will be

• A. $\frac{2}{3} \, ms^{- 1}$
• B. $\frac{1}{3} \, m \, s^{- 1}$
• C. $2 \, ms^{- 1}$
• D. zero

Answer 1

Answer: (B)

Apply impulse equation, along string

Impulse = $\Delta p$
$10 \, \times \, \frac{1}{2}=\left(10 \, + \, 5\right)v$
$v=\frac{1}{3}ms^{- 1}$