# Homework Help: Work of a pitcher on the ball

1. Nov 1, 2006

### goalieguy

A baseball leaves a pitcher's hand at a speed of 41.0 m/s. The mass of the baseball is 0.142 kg . Ignore air resistance. How much work has the pitcher done on the ball in throwing it?

I've tried using (1/2)mv^2, but there has got to be something weird going on, or i could just be using the wrong equation

thanks for any and all help

2. Nov 1, 2006

### goalieguy

work

i work it out and get the same thing every time i have tried it.
2.911 Joules is the answer I get, and WebAssign says that it is incorrect.

3. Nov 1, 2006

### Staff: Mentor

How are you getting that answer? Show what you did.

4. Nov 1, 2006

### goalieguy

sorry

Sorry about not showing all the work.

I just take the givens: v=41.0 m/s m=0.142 kg

Then I plug it in to: $$\frac{m*v^2}{2}$$

$$\frac{41*0.142}{2}$$

That is the answer i come up with (2.911 Joules)

5. Nov 1, 2006

### rsk

square your 41, boy!

6. Nov 1, 2006

### goalieguy

duh. thanks i knew i was doing something completely dumb.
always gotta forget the easy part.

right answer = 119.351 Joules

thanks a lot