Gravitational Potential Energy

Question

Amber throws a .25 kg ball straight up with a speed of 13m/s. How do I find out how high the ball goes? How do I use the speed given to find the energy so I can find the height? Right now I only have mass and gravity=9.8.

Answer 1

You need to use the law of conservation of energy.

In the beginning the ball has only kinetic energy K = 1/2 mv². At the top the ball has only potential energy U = mgh.

According to the law of conservation of mechanical energy K = U.

Or 1/2mv²= mgh. After cancelling mass, we will have for maximum height

h = v²/2g

Hope you can plug in the values of velocity and free fall acceleration by your own.

Interesting that the maximum height does not depend on mass of the body.