4.To make the rod move to the right at speed v, you need to apply an external force on the rod to the right. If l= B cm, B filed is D/50 T, v= B/5 m/s and R= A ?.

(a) Explain and determine the current I?

(b) determine the magnitude of the required force.

(c) What external power is needed to move the rod?

B= 137

D= 10

A= 27