# Projectile Motion pitching speed

1. Feb 6, 2010

### charan1

1. The problem statement, all variables and given/known data
A baseball player friend of yours wants to determine his pitching speed. You have him stand on a ledge and throw the ball horizontally from an elevation 4.00 m above the ground. The ball lands 30.0 m away.

Part A:
What is his pitching speed?

Part B:
As you think about it, you’re not sure he threw the ball exactly horizontally. As you watch him throw, the pitches seem to vary from 5° below horizontal to 5° above horizontal. What is the range of speeds with which the ball might have left his hand? Enter the minimum and the maximum speed of the ball.

2. Relevant equations
Sf=Si+Vis*T+.5aT^2

3. The attempt at a solution

For Part A I did the following:

Yf=Yi+Viy*T+(.5)(g)T^2

0m=4m+(0m/s)(T)+(.5)(-9.8m/s^2)(T^2)
T=.9035

Xf=Xi+Vix*T+(.5)aT^2

30m=0m+Vix(.9035 seconds)+(.5)(0m/s^2)(.9035^2)
Vix=33.204m/s

Part B:

I could only think to do the following...

cos(5)=33.2/h

h=33.3268....

2. Feb 6, 2010

### Spinnor

You need to remember the motion takes place in two dimensions. In the horizontal direction x = x_0 + v_xo*t. In the vertical direction
y = y_0 + v_yo*t + .5*a*t^2.

3. Feb 6, 2010

### charan1

I dont follow. My part A is already correct.

4. Feb 6, 2010