Amagnetic field has a magnitude of 1.20 10-3 t, and an electric field has a magnitude of 5.70 103 n/c. both fields point in the same direction. a positive 1.8-�c charge moves at a speed of 3.00 106 m/s in a direction that is perpendicular to both fields. determine the magnitude of the net force that acts on the charge.

Let's take the x,y,z axis such that the electric field E and the magnetic field B are on the x-axis and the velocity of the particle is on the y-axis.

The charge is .

The electric force acting on the charge is

and the direction is the same as the electric field, so on the x-axis.

The magnetic force acting on the charge is

and by using the right hand rule, we find that the direction of the force is on the z-axis.

So, the two forces Fe and Fb are perpendicular to each other. Therefore, the net force acting on the particle is the resultant of the two forces: