Determining Electric Charge of a Bullet in Earth's Magnetic Field

[cclement524]

1. Homework Statement
In a certain region, the Earth's magnetic field has a magnitude of 5.30e-5 T and is directed north at an angle of 57° below the horizontal. An electrically charged bullet is fired north and 11° above the horizontal, with a speed of 681 m/s. The magnetic force on the bullet is 2.90e-10 N, directed due east. Determine the bullet's electric charge, including its algebraic sign (+ or −).





2. Homework Equations

q = f / vBsin(theta)

3. The Attempt at a Solution

q = 2.90e-10 N / (681)(5.30e-5)(sin 11+57)

-9e-9

My answer is negative according to the right hand rule.

I'm wrong, but I don't know where I went wrong. If you could help me I would greatly appreciate it. Thank you!

 

[issacnewton]

Even I think its negative. The book's answer seems wrong.