Physics - SHM Question with Solution | TestHub

The period of a simple pendulum is given by $\begin{array}{rl}& T=2\pi \sqrt{\frac{L}{g}}\\ & \therefore T\propto \sqrt{L}\end{array}$ If the clock is running slow, that means time period is larger as compared to the correct value. So, by reducing the length of the pendulum the time period can be shortened to get the correct value.