# Homework Help: Transfer of torque

1. Sep 16, 2009

### KillerZ

1. The problem statement, all variables and given/known data
The clutch system shown in Fig. P10-22 is used to transmit torque through a 3-mm-thick oil film with $$\mu = 0.38 N \bullet s/m^{2}$$ between two identical 30-cm-diameter disks. When the driving shaft rotates at a speed of 1450 rpm, the driven shaft is observed to rotate at 1398 rpm. Assuming a linear velocity profile for the oil film, determine the transmitted torque.

2. Relevant equations

$$T = \mu\left(\frac{4\pi^{2}R^{3}\dot{n}L}{l}\right)$$

3. The attempt at a solution

$$\mu = 0.38 N \bullet s/m^{2}$$
$$L = 30cm = 0.3m$$
$$l = 3mm = 0.003m$$

This is where I am stuck I am not sure what R is. I think I have to find T for the two rpms and find the difference between them for the transferred torque.

2. Sep 17, 2009

### CFDFEAGURU

The units should tell you what R is. You have to get N-m out of this equation, so based on what you know (the given values) you can figure out what unit R will have and that will tell you what it's value should be.

Thanks
Matt

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