Question

A feather is dropped on the moon from a height of 7.2 m. The acceleration of gravity on the moon is 1.6 ms-2. Determine the time it takes for the feather to reach the surface of the moon.

Answer 1

Given:-

→Height from which the feather is

dropped=7.2m

→Acceleration due to gravity on the

moon =1.6m/s²

To find:-

→Time taken by the feather to reach

the surface of moon

Solution:-

In this problem:-

•Initial velocity of the feather will be zero as initially it was rest before dropping.

By using the 2nd equation of motion,we get:-

=>h=ut+1/2gt²

=>7.2=0×t+1/2×1.6×t²

=>7.2=0.8t²

=>t²=7.2/0.8

=>t²=9

=>t=√9

=>t=3s

Thus,the feather takes 3 seconds to reach the surface of the moon.

Some Extra Information:-

The three equations of motion for freely falling bodies are:-

•v=u+gt

•h=ut+1/2gt²

•v²-u²=2gh