# Finding change in momentum in 2-dimensions.

1. Jul 27, 2015

### Oxford365

To find the momentum change for an object in 2 dimensions do I find the initial momentum in both the x & y direction then apply the Pythagorean theorem, and then do the same for the final momentum and then find the difference between the two?

2. Jul 27, 2015

### Staff: Mentor

Momentum is a vector, so when you're looking for the change in momentum you're really looking for the difference between the initial an dthe final momentum vectors. Google for "vector subtraction Cartesian coordinates" and you'll find plenty of examples.

3. Jul 28, 2015

### Khashishi

If you just want the magnitude,
$\Delta p = \sqrt{(p_{1x} - p_{2x})^2 + (p_{1y}-p_{2y})^2}$