PHYS208 Fundamentals of Physics II

Hint for Ch. 29, 62P

It is easiest to consider the loops of wire to form a dipole.

[dipole in a field]

The torque created will be out of the page (screen) tending to rotate the spool up the incline.

The additional forces acting on the spool are the force of gravity mg, acting downward from the center of mass, the normal force of the incline N, acting perpendicularly to the incline through the center of mass, and the force of friction Ffric, acting up the incline at the point of contact.

Draw a free body diagram!

Set up Newton's second law for acceleration down the incline and Newton's second law for rotation about the center of the spool. Find the least current (least dipole moment) that will be required for both the linear acceleration and the angular acceleration to be zero.

Last updated Oct. 23, 1997.
Copyright George Watson, Univ. of Delaware, 1997.