Question

A 10kg rock and a 20 kg rock are dropped from the same height. If the takes the 20 kg rock a time t to reach the ground. What time will it take the 10 kg rock to reach the ground?

Answer 1

We have the next formula for freefall movement

`h=(vf)/(2)\cdot t`

The height is the same for both rocks also the vf (final velocity) because of the next formula where also the gravity is the same for both rocks.

`vf=\sqrt[]{2gh}`

then if we isolate the t (time) of the first formula

`t=(2h)/(vf)`

We notice that the time will it take the 10 kg rock to reach the ground is the same as the 20kg rock that is t.

therefore the answer is the same time as the 20kg rock that is t.