In the following figure a metal wire of mass m 238 mg can s

In the following figure, a metal wire of mass m = 23.8 mg can slide with negligible friction on two horizontal parallel rails separated by distance d = 2.56 cm. The track lies in a vertical uniform magnetic field of magnitude 56.3 mT. At time t=0, device G is connected to the rails, producing a constant current i = 91.3 mA in the wire and rails (even as the wire moves). At t = 61.1 ms, what is the wire\'s speed?

Solution

Magentic force, Fb = I L B

Fb = (91.3 x 10^-3 A) ( 0.0256 m ) ( 56.3 x 10^-3 T)

Fb = 1.316 x 10^-4 N

a = Fb / m = (1.316 x 10^-4) / (23.8 x 10^-6)

a = 5.53 m/s^2

Applying v = u + at

v = 0 + (5.53 x 61.1 x 10^-3)

v = 0.338 m/s