00:01
Here we're considering a wooden cylinder on an inclined plane where there is 10 loops of wire wrapped around the cylinder and a uniform magnetic field directed upward.
00:16
And the question that we want to answer is what is the smallest current eye that needs to go through the wire in order to keep the cylinder from rolling down? the inclined plane.
00:32
So if we're keeping the cylinder from rolling down the inclined plane, then it's in equilibrium and the sum of the torques on the cylinder must be equal to zero.
00:48
The torques that would produce rotation on the cylinder are going to be from the force of gravity acting on the cylinder because of its weight, as well as from, from the magnetic field with the current through the loops.
01:07
So the torque that is produced from the force of gravity, that's just going to be the weight of the cylinder, which is mg times the radius of the cylinder, which i'm going to label r here, because that is what our lever arm would be for that torque.
01:30
For the magnetic field.
01:37
The torque is given by, i'm going to label this tau -sub -b, is given by the magnetic dipole moment times the magnitude of the electric field.
01:49
And the magnetic dipole moment is n -i -a...