Question

Your roommate drops your wallet diwn to you from the third floor window of your apartment which is 11.5m form the ground. What is the velocity of the wallet when you catch it?

Answer 1

`v_f=15.01\ m/s`

Step-by-step explanation:

Free Fall Motion

If an object is dropped from a certain height h in free air (no friction), it falls to the ground with an acceleration of gravity (
`9.8\ m/s^2`). The speed of the object is given by

`v_f=g.t`

And the distance traveled downwards is

`\displaystyle y=(g.t^2)/(2)`

We can find the time the object is in the air before reaching ground level, solving the above equation for t as follow

`\displaystyle t=\sqrt{(2y)/(g)}`

`\displaystyle t=\sqrt{(2(11.5))/(9.8)}`

`t=1.532\ sec`

Now we compute the speed

`v_f=9.8(1.532)=15.01\ m/s`

`\boxed{v_f=15.01\ m/s}`