Question

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

• A. zero
• B. 5 m
• C. 2.5 m
• D. 1.25 m

Answer 1

Answer: (D)

1.25 m

by conservation of momentum principle the final velocity right after collision is $v=\frac{100}{2}=50cm/sec$
Hence by conservation of energy theorem $\frac{1}{2}m{v}^2=mgh$
$⟹h=10\times \frac{1}{2}{0.5}^2=1.25m$