# Homework Help: Force on an electron from a magnetic field

1. Jun 23, 2008

### brett812718

1. The problem statement, all variables and given/known data
A 17.0 g block with a charge of +1.30 10-4 C is placed in an electric field e vector = (2000 i hat - 200 j hat) N/C.
(a) What is the electrostatic force on the block?
the force is 2.61E-1N but I am having trouble finding the angle.

2. Relevant equations
F=qE

3. The attempt at a solution
180+tan^-1(-200/2000)=174.3 degrees but webassign said it was wrong.

Last edited: Jun 23, 2008
2. Jun 23, 2008

### brett812718

sorry the title should have said force on an electron from an elecrtic field

3. Jun 23, 2008

### Zizy

You might try writing only tan^-1 part (so you get like 6 degrees) and test this solution. Or use 90 instead of 180 deg... some diagram which angle are you looking for would be helpful.

4. Jun 23, 2008

### brett812718

I am looking for the angle made by F and the positive x axis

5. Jun 23, 2008

### brett812718

F is in the opposite direction of E right?