Question

For a sine wave depicting simple harmonic motion, the smaller the amplitude of the wave, the smaller the displacement of the pendulum from the equilibrium position. The shorter the period, the ? the pendulum’s rod.

Answer 1

Shorter the pendulum rod, as the period of a pendulum is solely dependent on the length of the pendulum.

Answer 2

The correct answer is

The shorter the period, the shorter the pendulum’s rod

In fact, the period of a simple pendulum is given by:

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

where T is the period, L is the length of the pendulum's rod, g is the gravitational acceleration. We immediately see from the formula that T and L are proportional: therefore, if the period T is shorter, the length of the pendulum's rod L is shorter as well.