### Home > PC3 > Chapter 13 > Lesson 13.2.3 > Problem 13-89

13-89.

A water balloon is tossed from the top of a walkway so that its height above the ground is found by where

*is measured in feet and*

*is measured in seconds.*

When will the ball reach a maximum height?

The given function is a parabola. Where is the vertex of this parabola?

When will the ball hit the ground?

This occurs when

.Approximate the instantaneous velocity of the water balloon when it strikes the ground.