Question

An object is allowed to fall freely near the surface of an unknown planet. The object falls 80 meters from rest in 5.0 seconds. The acceleration due to gravity on that planet is?

Would the answer be 16?

Answer 1

The equation of kinematics for an object under freefall from rest:
h = v0 t + (1/2)at²
initial velocity, v0 = 0 m/s
acceleration, a m/s/s
height dropped, h m
time to drop, t seconds
Solve for a.

Answer 2

Half the acceleration is 16. I got 32 m/s^2 for the planet's acceleration.