Chapter 3 - Help Please

Question

A 10-lb rock and a 5-lb rock are dropped simultaneously from the same height. Some say that because 10-lb rock has 2 times much force acting on it as the 5-lb rock, it should hit the ground first. Do you agree? Please explain your point. Also, describe similar situation if the rocks were dropped by an astronaut on the Moon.

Answer 1

Heavy objects and light objects, or any object at all, have the same acceleration due to gravity. All objects accelerate toward earth at 9.8 m/s² (assuming air resistance is ignored). So a 10 pound rock will hit the ground at the same time as a 5 pound rock, or even a 1000 pound rock.

If these rocks were dropped on the moon, they would take a different amount of time to hit the ground than they did on Earth but, again, they would hit at the same time as each other.