# Physics 12: electromagnetism problem -- Find the acceleration of the proton in a B-field

Tags:
1. May 30, 2017

### marysaf

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

A proton is accelerated from rest at the positive plate of two charged parallel plates with a potential difference of 2000 v. After leaving the plates through a small hole in the negative plate, it enters a uniform magnetic field of 0.50 T in a direction perpendicular to the magnetic field directed out the page as shown in the diagram. Find the acceleration of the proton.

2. Relevant equations

a=v^2/2d

3. The attempt at a solution

I tried to use the equation above but I don't have d and don't know how to find it. should I use f=ma?

Last edited by a moderator: May 30, 2017
2. May 30, 2017

Yes.

3. Jun 3, 2017

### rude man

F = qvB also helps.

4. Jun 4, 2017

### Mariz

There are two accelerations in this problem.
The linear one, between the plates.
To find this one you must find first the final velocity. Use energy to do that.

The centripetal one. In the magnetic field. Do find this use F=qvB sin(theta).