00:01
Hi there.
00:01
So for this problem, we are talking to consider a 55 centimeters long journal that is bering that is lubricated with an oil whose viscosity is given at the beginning of the operation and later changes at the anticipated steady operated temperature of 80 degrees.
00:22
So the diameter of the shaft is 8 centimeters and the average gap between the shaft and the journal is 0 .08 centimeters.
00:30
So we need to determine the torque needed to overcome the bearing friction initially endured in the steady operation when the shaft is rotating at a frequency that is equal to 1 ,500 revolutions per minute.
00:54
So with that said, we note that the formula to find the torque is given by the following expression.
01:05
That is equal to mu, which is the viscosity of the liquid, in this case the oil, times 4 times pi to the square, and this times the radius of the shaft to the 3, and this times the velocity of the shaft, this times the distance alt, the length out, and this divided by just simply the gap between the shelf and the bearing, let's call this lowercase l...