1. 2 in
G=0.002 in
Calculate the required torque in lbf-ft and heat loss (power consumption) in horsepower to turn the shaft on the friction bearing shown. You may assume the length of the bearing surface on the shaft is 2 inches, that the shaft is turning at 200 rpm, that the viscosity of the lubricant is 200 cp., and that the fluid density is 50 lbmft-3.

2. 0.012 Hp

3. T = r x F
T = Ri x F = RiFk
What is the tangential force acting on the shaft?
[Use cylindrical coordinates]
The force resisting the turning motion will be applied to the r-plane in the q-direction. F = trqA

4. T = r x F
T = RitrqAk = RitrqRiLk
T = 2pRi2Ltrqk = 2pRi2LmwRik = 2pmRi3wL k
G G
T = k 2p(2.00 g cm-1s-1)(2.54 cm)3(20.9 s-1)(5.08 cm) = x 106 dyne cm k
( cm)
T = 4.30 x 106 dyne cm k = ft-lbf k