Two long, smooth conducting rails are connected to a 12 V battery of negligible…
MATHEMATICS · Multi-part · A Level · Mathematics · Forces and Newton's laws · Forces and Newton's laws
Problem
Two long, smooth conducting rails are connected to a 12 V battery of negligible internal resistance. A uniform magnetic field of 0.50 T acts vertically downward over the central 0.60 m length of the rails. A metal rod of length 0.30 m and mass 0.20 kg is placed across the rails so that it can move freely without leaving contact. The resistance of the rod is 0.50 Ω while the resistance of the rest of the circuit is 1.50 Ω. The rod is released from rest at the left edge of the magnetic field region and allowed to move only under the forces acting on it.
(a) Calculate the current in the circuit when the rod is within the magnetic field.
(b) Find the magnitude and direction of the magnetic force acting on the rod at that moment.
(c) Compute the acceleration of the rod while it is inside the magnetic field, neglecting friction.
(d) The rod emerges from the right edge of the field after travelling 0.60 m. Determine its speed at that instant.