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Homework Statement
a 3 microcoulomb charge having a speed of 10m/s is fired into a region of constant magnetic field where B is given by:
B = 0.3i - 0.4j
a) the magnitude force on the charge is found to be 2*10^-6 Newtons. what is the angle between v and B?
b) if the direction of v is changed so that the charge moves along the +z direction at a speed of 10m/s, what would be the magnitude and direction of the magnetic force in this case?i am supposed to get 7.66 degrees for part a, and 15*10^-6 Newtons at 36.9 degrees for part b
Homework Equations
radius r = mv/qB where m is mass, v is velocity, q is charge, B is magnetic field
electromagnetic force, F = qE + qv X B where X indicates cross product, E is electric field
The Attempt at a Solution
part a:
using F = qE + qv X B ----> find theta
F = qE + qv X B
2*10^-6 = (3*10^-6E) + ((3*10^-6)(10)(0.3i - 0.4j)sin(theta))
sin(theta) = 2*10^-6 - 3*10^-6E/((3*10^-6)(10)(0.3i - 0.4j))
theta = inverse sin((2*10^-6 - 3*10^-6E)/(9*10^-6i - 1.2*10^-5j)) holding electric field E constant
is this the correct approach to find theta?
i haven't started part b yet, but i am assuming theta changes to (theta from part a + 90 degrees) and i just substitute that new theta into the electromagnetic force equation to solve for force.
is my approach for part a, correct? how about part b? or am i using the wrong equation?
i am supposed to get 7.66 degrees for part a, and 15*10^-6 Newtons at 36.9 degrees for part b
any help appreciated
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