Earth's magnetic force on a proton

[Jaccobtw]

Homework Statement

A proton is flying to the east near the surface of the earth at 1000m/s. What is the magnitude of the force (in N) the proton feels due to the earth's magnetic field?

Relevant Equations

F = qvBsin$\theta$

Plug in the elementary charge for q, 1000 m/s for v, 50 microtesla for B and 90 degrees for theta and I get about 8e-21 Netwons. But apparently this is wrong, anyone know why? Thank you.

 

[TSny]

Your calculation looks correct. The problem statement as given doesn't provide the strength of the B-field. The field varies quite a bit over the surface of the earth. Why did you choose 50 μT?

 

[Jaccobtw]

Your calculation looks correct. The problem statement as given doesn't provide the strength of the B-field. The field varies quite a bit over the surface of the earth. Why did you choose 50 μT?

google!

 

[TSny]

google!

Click on the "varies quite a bit" in my previous post.