9.) Why would a pendulum swing faster or slower on different planets?

The longer the length of string, the farther the pendulum falls; and therefore, the longer the period, or back and forth swing of the pendulum. Since the force of gravity is less on the Moon, the pendulum would swing slower at the same length and angle and its frequency would be less. So, the longer the pendulum, whether it is a string, metal rod or wire, the slower the pendulum swings. Conversely the shorter the pendulum the faster the swing rate.

Explanation:

When continental and oceanic plates collide, the thinner and more dense oceanic plate is overridden by the thicker and less dense continental plate. The oceanic plate is forced down into the mantle in a process known as "subduction." As the oceanic plate descends, it is forced into higher temperature environments.