Answer:
a) -z direction, b) +z direction, c) F=0
Explanation:
The magnetic force is given by the expression
F = q v x B
the bold indicate vectors, this equation can be separated in its module
F = a v B sin θ
and where θ is the angles between the speed and the magnetic field.
The direction of the force can be found with the right-hand rule. For a positive charge, the thumb goes in the direction of speed, the fingers extended in the direction of the magnetic field and the palm points in the direction of the force, if the charge is negative the force is in the opposite direction.
a) Let's apply this to our case
the proton is positively charged
moves in the direction of + x
The magnetized field goes in the direction of y
therefore applying the right hand rule the force must be in the direction of the negative part of the z-axis (-z)
The right-hand rule is used to find this address.
b) in this case it indicates that the proton moves in the recode of -y
again we apply the right hand rule and the force is in the direction of + z
c) The proton moves in the x direction
In this case the force is zero because the angle between the field and the speed is zero and the sine is zero, therefore the force is zero