# Homework Help: Torque and angular momentum for a Particle in a Force Field

1. Apr 17, 2008

### so09er

[SOLVED] Torque and angular momentum for a Particle in a Force Field

Find A) the torque and B) the angular momentum about the origin at the time t=3 for a particle in a Force Field F=(3t^2 -4t)i + (12t -6)j + (6t - 12t^2)k. Assuming that t=0 is located at the origin.

I equated r"=F then took r X F is this the proper way? Then took r X v to find angular momentum. Any help would be appreciated.

2. Apr 17, 2008

### Dick

Yes, that's the right way. Solve the differential equation r''=F and find v and r at t=3. You not only need to assume r(0)=(0,0,0), you need some initial condition for r'(0). Is it also (0,0,0)?

3. Apr 18, 2008

### so09er

Thanks for the confirmation