Rail gun and magnetic field question

[Turpulus]

Homework Statement

The planet Zargon has a magnetic field that is oriented the same as Earth’s, but has a magnitude of 1.26 T! A Royal Zargon Warrior is exploring the Badlands at the Zargon equator when he senses that a vicious octomorph is on top of the rock pillar 9.50 m above him. He dare not move from his position, facing due East, for fear that the octomorph will see him. His rail gun, which has a varible muzzle velocity, shoots pellets of mass 4.00 g, that carry a charge of +1.60 C. What muzzle velocity should the Zargon Warrior adjust his rail gun to in order to kill the octomorph?

Homework Equations

F=qvbsintheta
F=mg

The Attempt at a Solution

So if he shoots the particle due east, the particle will deflect upward in a circular path with radius =mv/(qB), you want r to be 9.5m/2 = 4.75m, and the rest is algebra. Therefore I got a velocity of 2,394m/s. Is this correct?

 

[ehild]

Yes, 2394 m/s for the muzzle velocity is correct.

ehild