Question

An object is dropped from the top of a building. How fast is it moving after 5s? What is the acceleration at this time?

Answer 1

Any object under free fall accelerates at a constant rate given by the gravitational acceleration:

`g=9.81(m)/(s^2)`

On the other hand, the speed v of an object under free fall after t seconds, if it starts from rest, is given by the formula:

`v=gt`

Replace g=9.81m/s^2 and t=5s to find the speed of the object 5 seconds after the object is dropped:

`v=(9.81(m)/(s^2))(5s)=49.05(m)/(s)`

Therefore, the speed of the object after 5 seconds is approximately 49 meters per second. Its acceleration is always the same and it is equal to 9.81 meters per second squared.