*56.  A golf ball is dropped from rest from a height of 9.50 m. It hits the pavement, then bounces back up, rising just 5.70 m before falling back down again. A boy then catches the ball on the way down when it is 1.20 m above the pavement. Ignoring air resistance, calculate the total amount of time that the ball is in the air, from drop to catch.

 

 

The total time the ball is in the air is the sum of the time for each of the three parts of this motion, the fall from 9.50 m, the rise to 5.70 m, and the fall to 1.20 m.  The fall from 5.70 m to 1.20 m is a fall of 4.50 m.

 

 

We will make use of the fact that under a constant acceleration (due to gravity) the times to rise and fall are the same.  For an object falling from rest a height h, we can use

 

Since we are falling from rest we know , and y is h and a is g

 

Solving for t

Now figure out each fall time for each height

 

 

 

 

 

 

 

Please send any comments or questions about this page to ddonovan@nmu.edu

This page last updated on January 11, 2020