Question

A mass of $10gm$, moving horizontally with a velocity of $100cm/\sec$, strikes the bob of a pendulum and strikes to it. The mass of the bob is also $10gm$ (see fig.) The maximum height to which the system can be raised is ($g = 10m/\sec^{2}{}$)

• A. Zero
• B. $5cm$
• C. $2.5cm$
• D. $1.25cm$

Answer 1

Answer: (D)

$1.25cm$

Answer 2

By the conservation of momentum,

Momentum of the bullet = Momentum of system ⇒

$10 \times 1 = (10 + 10) \times v$ ⇒ $v = \frac{1}{2}m ⥂ / ⥂ s$

Now maximum height reached by system

${H\frac{v^{2}}{2g}\frac{(1/2)^{2}}{2 \times 10}}_{\max}$.