Have you ever wondered how fast can you pitch a ball? In an flat open field mark your position. You know that if you throw the ball horizontally it will fall to the ground as the ball accelerates downward.

Materials: tennis ball (or baseball) and any ruler or string.

1. Measure the height H of the ball in meters as it leaves your hand. Practice a few simulations to be sure this height is precise.

2. Now throw the ball horizontally as hard as you can. This is very important for the success of the experiment. Practice a few times.

3. When you are ready, measure the range R of the ball (in meters).

4. Repeat this experiment at least three times. Ask your partner to do the same.

5. Find the flight time T of the ball from the free fall equation:

                             H = (g*T^2) /2 , g = 9.8 m/s^2

6.The initial velocity v of the ball in the horizontal direction will then be

                             v(initial) = R/T

7. Report the velocities for each trial, the average velocity for the three trials and the % error of the average (see instructions in Exp.1). Do a separate analysis of your partner's data.

8. Professional players can pitch a ball to speeds of 100 mph or about 44.5 m/s. What fraction of that speed can you achieve?

9. Discuss sources of error.