Question

1, A simple pendulum 0.4m long as a period of 1.3sec. what is the period of a similar pendulum 0.3m long in the same location.

Answer 1

$T=2\pi\sqrt{\frac lg},$

$T\sim \sqrt l,$

$T_2=T_1\sqrt{\frac{l_2}{l_1}}=1.1~s.$