Consider a conducting rod of length 34 cm moving along a pair of rails, and a magnetic field pointing perpendicular to the plane of the rails. Required:
At what speed (in m/s) must the sliding rod move to produce an emf of 0.75V in a 1.75T field?

I'm not sure what your asking buddy.. but i know that you can weld two peices of steel by pure force and pressure.

The magnets are probably damaged or there not strong enough to attached to the refrigerator

Ithink c because you have to work to become goid

Distance covered = speed x timethe distance traveled going against the stream = distance traveled with the stream.therefore it is the speed and the time that are the variables.as he travels the same distance both ways, speed x time is the same for each way.going upstream his speed is 4 kph; going downstream his speed is 6 kph.therefore we have two simultaneous equations: time upstream x 4 = time downstream x 6time upstream + time downstream = 60 minutestherefore we have the equation: time upstream = 6/10 hour, time downstream therefore = 4/10 hour.distance traveled at 4km/hr in 6/10 hour = 24/10 = 2.4km.check: distance traveled at 6km/hr in 4/10 hour = 24/10 = 2.4km.