# Impulse and Momentum Problem

1. Aug 6, 2009

### crono_

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

From Cutnell & Johnson PHYSICS 7th Edition Textbook - Ch 7 / Problem #1

One average force F1 has a magnitude that is three times as large as that of another average force F2. Both forces produce the same impulse. The average force F1 acts for a time interval of 3.2 ms. For what time interval does the average force F2 act?

2. Relevant equations

Note sure. I think...Impulse-Momentum Theorem

Ft = mvf - mvo

3. The attempt at a solution

No serious attempt made. I get tripped up in the wording of the problem. Any help would be appreciated.

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

2. Relevant equations

3. The attempt at a solution

2. Aug 6, 2009

### kuruman

The impulse is the product F*t as you say. If the impulses for the two forces are the same, we can say this with an equation. Use this to say that Impulse 1 is the same as Impulse 2 with an equation.

3. Aug 6, 2009

### crono_

Thanks for the explanation, though truthfully I'm still not getting it...

4. Aug 6, 2009

### kuruman

Let's try this.

Impulse 1 = F1t1
Impulse 2 = F2t2

The problem says the impulses are equal. This means that

F1t1=F2t2

Can you finish from here? Don't forget to say with an equation that F1 is three times F2.

5. Aug 6, 2009

### crono_

I'm inclined to write it as:

(3F1t1) = (F2t2)

Still thinking about the next step...

6. Aug 6, 2009

### kuruman

You replaced F1 with three times itself. Can F1 be the same as 3F1? What is F1 the same as? Re-read the question.