# Find the magnitude and direction of the sum of momenta

1. Jul 6, 2007

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

An 85 kg jogger is heading due east at a speed of 2.2 m/s. A 55 kg jogger is heading 20° north of east at a speed of 4.0 m/s. Find the magnitude and direction of the sum of momenta of the two joggers.

2. Relevant equations

The Impulse-Momentum Theorem

3. The attempt at a solution

I tried to get the components of the 2 vectors, add them, and get the answer...but I got the wrong answer apparently. Should I try again?

2. Jul 6, 2007

### Staff: Mentor

Yes, try it again--that's the right method. Remember that you are adding momenta, not just velocity vectors.

This has nothing to do with the impulse-momentum theorem.

Also: Try to give your posts more descriptive titles that "Help!".

3. Jul 6, 2007

haha well obviously "help" gets a much desired response =) but i'll keep that in mind. and webassign is wrong a lot. it said to use the theorem. how would i use momenta instead?

4. Jul 6, 2007

Ok, I got it. Thanks!

5. Jul 6, 2007

### Staff: Mentor

Don't worry about the getting help part--that's what the "homework help" forums are for. But if all your posts have the same title, busy homework helpers might think they've already answered your question--thus you end up getting less help than you might need.
That's what I thought you already tried. Find the components and add them up. This is an addition of vectors problem, not an impulse-momentum problem. (Unless there is more.)

6. Jul 6, 2007

Good! ....