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A metal wire of mass m slides without friction on two horizontal rails spaced a

ID: 1763369 • Letter: A

Question

A metal wire of mass m slides without friction on two horizontal rails spaced a distance d apart, as in the figure below. The track lies in a vertical uniform magnetic field . Generator G produces a constant current i in the wire and the rails (even as the wire moves). Find the velocity of the wire's motion as a function of time, assuming it to be stationary at t = 0. (Use m, d, B, i and t as necessary, where all quantities are in SI units. Enter the sign of the expression, taking right to be positive.) v =

Explanation / Answer



   Given that themass of conductor is m    currentis i      Magnitude of magnetic field is B    Lengthof conductor is d -------------------------------------------------------------------------
   The force on the conductor is F = BiL    Then the acceleration is    a = F / m          a =BiL / m          dv / dt = BiL / m          dv =( BiL / m ) dt    integrating bothsides then          v= ( BiL ) t / m