Question

A ball is dropped from a rooftop 60m high.
How long is the ball in the air?

Answer 1

Answer: 3.49 s

Step-by-step explanation:

We can solve this problem with the following equation of motion:

`y=y_(o)+V_(o)t-(1)/(2)gt^(2)` (1)

Where:

`y=0 m` is the final height of the ball

`y_(o)=60 m` is the initial height of the ball

`V_(o)=0 m/s` is the initial velocity (the ball was dropped)

`g=9.8 m/s^(2)` is the acceleratio due gravity

`t` is the time

Isolating
`t`:

`t=\sqrt{(2 y_(o))/(g)}` (2)

`t=\sqrt{(2 (60 m))/(9.8 m/s^(2))}` (3)

Finally we find the time the ball is in the air:

`t=3.49 s` (4)