# Homework Help: Velocity filter question

1. Aug 28, 2011

### jforce93

1. The problem statement, all variables and given/known data
In the figure (see attached) what is the velocity of the charged particle to the nearest tenth of a m/s that will allow it to travel undeflected through the crossed magnetic field if E = 6852 N/C and B = 3.6 T?

2. Relevant equations

F = E*q + q*V*B

3. The attempt at a solution

Okay, so this is an online physics practice thing (for Giancolli) I was assigned for AP work. It's known for giving wrong (but close) answers, so don't be afraid to tell me that I'm doing this right (or wrong). But the answer I got is very close to the answer it gave me.

Anyway, here is my attempt:

E*q = q*V*B
cross out q

E = V*B

V = E/B

E = 6852 N/C
B = 3.6 T

V = 1903.3 m/s

Thanks,

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

2. Relevant equations

3. The attempt at a solution

#### Attached Files:

• ###### mag4.gif
File size:
1.2 KB
Views:
181
2. Aug 28, 2011

### PeterO

Calculations look OK. Given the original data - especially the B = 3.6 - it indicates you should only give your answer to 2 figures, so 1.9 x 103 m/s

note that 1900 m/s is not correct, because if you, even mistakenly, decide to give too many figures, those extra figures have to be correct.

3. Aug 28, 2011

### jforce93

Thanks!
And the online thing doesn't let us (for most questions) put in scientific notation

4. Aug 28, 2011

### PeterO

In that case, 1900 might be "their" form of 1.9 x 103