# Angular momentum and Torque

1. Jan 13, 2017

### agargento

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

A 2.9-kg particle P is located at [(r)\vec] = 3.3 m [^(x)] + 1.8 m [^(y)] from the origin of the x-y coordinate system shown in the Figure. It moves with a velocity of [(v)\vec] = −4.1 m/s [^(x)] + 2.6 m/s [^(y)]. A force, [(F)\vec] = 2.7 N [^(x)] + 1.4 N [^(y)] acts on the particle.

a) What is the magnitude and direction of the angular momentum of the particle with respect to the origin of the coordinate system?
b) What is the magnitude and direction of the torque acting on the particle with respect to the origin of the coordinate system?

2. Relevant equations

L = r x mv
T = r x F

3. The attempt at a solution

At first I tried to take the magnitude of the radius r, the mangitude of v, and multiply by the mass. But this doesn't give me the direction... I also tried taking the cross product but it didn't go well, I got confused with the direction and the multiplication... would love some guidance.

Edit: Got the answer. Sorry for littering the forum ;)

Last edited: Jan 13, 2017
2. Jan 13, 2017

### Staff: Mentor

It also won't give you the correct magnitude if you ignored the angle between the vectors...
Show the details of your attempt using the cross product method. We can't critique what we can't see