# Help with acceleration, magnitude, and direction of force

1. Oct 20, 2008

### jayyafeelme

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

As a baseball is being caught, its speed goes from 28.0 m/s to 0.0 m/s in about 0.0050 s. The mass of the baseball is 0.140 kg.

What is the baseball's acceleration?
What are the magnitude and direction of the force acting on it?
What are the magnitude and direction of the force acting on the player who caught it?

2. Relevant equations

f=ma?

3. The attempt at a solution

28.0 m/s x 0.140 kg = 3.92

2. Oct 20, 2008

### LowlyPion

You calculated momentum. The force will be change in momentum over the time period.

If v = a*t you should be able to figure the acceleration.

3. Oct 20, 2008

### jayyafeelme

so 28.0 m/s x 0.0050 s?

4. Oct 20, 2008

### LowlyPion

Not the way I do algebra.

5. Oct 20, 2008

### jayyafeelme

v divided by 0.0050 s? please help me i really need to get this done

6. Oct 20, 2008

### LowlyPion

That gives you acceleration.

7. Oct 20, 2008

### jayyafeelme

but isnt v = velocity? and v = distance/time? they dont give me a distance

8. Oct 20, 2008

### jayyafeelme

someone help please

9. Oct 21, 2008

### borgwal

Can you do better than randomly multiplying quantities? Pion gave you v=a*t, which quantities do you know in this equation?

10. Oct 21, 2008

### jenglish

you're going to need an equation that can find the acceleration (or deceleration) when given an initial as well as final velocity and time.

I suggest

Vf=Vo+at

that should give you acceleration

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