A simple pendulum is made of body which is a hollow sphere containing mercury suspended by means of a wire. If a little mercury is drained off, the period of the pendulum will

Question

A simple pendulum is made of body which is a hollow sphere containing mercury suspended by means of a wire. If a little mercury is drained off, the period of the pendulum will (A) remain unchanged (B) increase (C) decrease (D) become erratic

Tardigrade Admin · Accepted Answer

As mercury drains off, the centre of mass of the sphere is lowered. Hence the effective length of the pendulum, the distance between the point of support and the centre of mass of the both increases.

T = 2 π \frac{l}{g}

, so

T

increases as well

Q. A simple pendulum is made of body which is a hollow sphere containing mercury suspended by means of a wire. If a little mercury is drained off, the period of the pendulum will

remain unchanged

increase

decrease

become erratic

As mercury drains off, the centre of mass of the sphere is lowered. Hence the effective length of the pendulum, the distance between the point of support and the centre of mass of the both increases. T=2πgl​​, so T increases as well

As mercury drains off, the centre of mass of the sphere is lowered. Hence the effective length of the pendulum, the distance between the point of support and the centre of mass of the both increases.
$T = 2 π \frac{l}{g}$ , so $T$ increases as well