A rigid copper wire is held horizontally between the pole pieces of two magnets, as shown in the figure below.
The width of each pole piece is 
. The uniform magnetic flux density 
in the region between the poles of the magnets is 
and is zero outside this region. The angle between the wire and the direction of the magnetic field is 
. The current in the wire is in the direction shown in the figure above.
By reference to the side view of the figure above, state and explain the direction of the force on the magnets.
The constant current in the wire is 
.
For angle equal to 
, calculate the force on the wire.
The angle is changed to 
. The length of wire in the magnetic field is 
. Calculate the force on the wire.
.
