Question

An object dropped from rest on a planet takes 7.17 seconds to reach a velocity of -58.1 m/s. The acceleration due to gravity is?

Answer 1

We can find the acceleration due to gravity on the planet from the kinematic equation:

$$v=v_0+gt,$$ $$g=\dfrac{v-v_0}{t}=\dfrac{-58.1\ \dfrac{m}{s}-0}{7.17\ s}=-8.1\ \dfrac{m}{s^2}.$$

The sign minus means that the acceleration of gravity directed downward.