Question

A certain pendulum has a period of 1.7s on Earth. What is the period of this pendulum on a planet that has a gravitational acceleration of 15m/s 2. 

Answer 1

Given:

$T_E=1.7\:\rm s$

$g_E=9.8\rm \: m/s^2$

$g_P=15\rm \: m/s^2$

The period of oscillation of a simple pendulum

$$T=2\pi\sqrt{\frac{l}{g}}$$

Hence

$$T_P=T_E\sqrt{\frac{g_E}{g_P}}=1.7\sqrt{\frac{9.8}{15}}=1.4\:\rm s$$