Astronauts on a distant planet set up a simple pendulum of length 1.2 m. The pendulum executes simple harmonic motion and makes 100 complete oscillations in 450 s. What is the magnitude of the acceleration due to gravity on this planet?

Answer 1

use this formula, and memorize it.

Period=2PI sqrt(length/g)

solve for g
Period is 4.5 seconds

Answer 2

10.8