Consider the specific example of a positive charge q moving in the +x direction with the local magnetic field in the +y direction. In which direction is the magnetic force acting on the particle? Express your answer using unit vectors (e. g., i^- j^). (Recall that i^ is written \hat i (or alternatively i_unit can be used.))

Therefore the direction is in the positive direction of the z axes.

Explanation:

Let's recall that the magnetic force is given by:

The unit vector of V is and the unit vector of B is

So, the direction of the force will be defined as the cross product of i and j, and using the right hand rule:

Therefore the direction of the magnetic force is in the positive direction of the z axes.

I hope it helps you!

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.