Magnetic information on hard drives is accessed by a read

Chapter 24, Problem 35P

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Problem 35P

Magnetic information on hard drives is accessed by a read head that must move rapidly back and forth across the disk. The force to move the head is generally created with a voice coil actuator, a flat coil of fine wire that moves between the poles of a strong magnet, as in Figure P24.37. Assume that the coil is a square 1.0 cm on a side made of 200 turns of fine wire with total resistance 1.5 Ω. The field between the poles of the magnet is 0.30 T; assume that the field does not extend beyond the edge of the magnet. The coil and the mount that it rides on have a total mass of 12 g.

a. If a voltage of 5.0 V is applied to the coil, what is the current?

b. If the current is clockwise viewed from above, what are the magnitude and direction of the net force on the coil?

c. What is the magnitude of the acceleration of the coil?