# Homework Help: Finding the total momentum

1. Dec 6, 2013

### jimmyboykun

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

two persons on ice skates stand face to face and then push each other away. their masses are 52 kg and 77 kg. what is the total momentum after they have pushed off

2. Relevant equations
the equation that would be most useful here would be P=Pa+Pb the equation for total momentum

3. The attempt at a solution

Im stump on this problem. Two mass are given, but no velocity is displayed. can someone explain to me.

2. Dec 6, 2013

### Jilang

Is there any other equation involving momentum that you think could be relevant?

3. Dec 6, 2013

### jimmyboykun

well I can think of the conservation of momentum equation: m1v1(initial)+m2v2(initial)=m1v1(final)+m2v2(final)

you think I can use this equation?

4. Dec 7, 2013

### Jilang

Yes that's a good equation!

5. Dec 7, 2013

### Dan350

Momentum is initially zero,, what clues does that give you

6. Dec 7, 2013

### jimmyboykun

that the final momentum will be given with their respected velocities.

0+0=52kgv1(final)+77kgv2(final). But I still don't see a way to solve this. Unless I factor the v(final)?

7. Dec 10, 2013

### jimmyboykun

after reviewing it I realize that the total momentum would zero. Because of the fact that only the masses are given and there's no other way to compute this.