A conducting rod of mass M with negligible electrical resistance slides on a pair of frictionless, horizontal, parallel, conducting rails separated by a distance L. The two rails are connected by an electrical resistance of R. A uniform magnetic field B is directed vertically upward in the entire region. a. Looking from above, is the conventional current flowing cw or cow? b. Determine the current through the resistor. c. Find the force necessary to keep the rod moving at a constant speed.

Explanation:

Given

mass of rod is M

Distance between rails is L

If the direction of magnetic field is directed upwards

If rod is moving right then,

Area enclosed is increasing therefore a Clockwise current will induce

and if rod is moving left then enclosed area is decreasing therefore an anticlockwise current will setup in the circuit

(b)Induced EMF will be

where v=velocity of rod

and current is

(c)Force necessary to move rod with constant velocity v is

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 chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.