A particular magnetic field points west. A proton moved from north to south. What direction is th magnetic force on the proton?

Up,down,east or northwest

To determine the direction of the magnetic force on a moving charged particle, you can use the right-hand rule. Here's how to apply it in this scenario:

1. Extend your right hand and point your thumb in the direction of the moving charged particle's velocity, which is from north to south in this case (downward).
2. Then, extend your index finger in the direction of the magnetic field, which points west in this case (to the left).
3. Now, curl your other fingers towards your palm. The direction your fingers point to represents the direction of the magnetic force exerted on the proton.

In this case, if you follow the steps, your curled fingers would point towards the northwest direction. Therefore, the magnetic force on the proton would be towards the northwest.