# Highest point on trajectory of tennis ball

1. Nov 4, 2009

### firebird99

1. The problem statement, all variables and given/known data

A tennis ball is thrown toward a vertical wall with a speed of 21.0 m/s at an angle of 40.0 degrees above the horizontal. The horizontal distance between the wall and the point where the tennis ball is released is 23.0 m.

a. At what height above the point of release does the tennis ball hit the wall?

b. Has the tennis ball already passed the highest point on its trajectory when it hits the wall? Justify your answer.

2. Relevant equations

3. The attempt at a solution

Sorry i can't provide more information but my teacher assigned us this problem, he said it would be difficult and honestly I have no idea what to do. Any help will be appreciated.

Thank-you

2. Nov 5, 2009

### tiny-tim

Welcome to PF!

Hi firebird99! Welcome to PF!

Use the standard constant acceleration equations for the x and y directions separately, to get two equations for t and h, and then eliminate t.