What is the magnitude? What is the direction? (up, down, left, right, intopage o
ID: 1511057 • Letter: W
Question
What is the magnitude? What is the direction? (up, down, left, right, intopage out of page)
Please provide an explanation, especially for the direction. Thank you
Hinge line (c29p39) The figure shows a rectangular, 20-turn coil of wire, 12 cm by 4 cm. It carries a current of 0.080 A and is hinged along one long side. It is mounted in the xy plane, at an angle of 30° to the direction of a uniform magnetic field of 0.60 T. Find the magnitude and direction of the torque acting on the coil about the hinge line.Explanation / Answer
Only the long leg of current will produce a torque, and the force on this outer leg is;
F = (NiL)(-k) X [(Bx)i + (By)j]
= (NiLBx)j - (NiLBy)i
Only the "j" component of F will produce a torque.
The torque is;
Torque = (r)i X (NiLBx)j
= [rNiLBCos(30)](-k)
= [(.04)(20)(.080)(.12)(.60)(.866)](-k)
= [3.990645061 x 10^-3 N-m](-k)