Problem sheet 10

The numbers in square brackets refer to the number of the problem in your textbook.

1. [E11.6] A 30 mm diameter plane bearing of length 20 mm is to be made of a material with the P-v characteristics shown in Figure 1.11 (b). If the bearing load is 300 N and the maximum rotation rate is 500 rpm, is it safe to run it dry? if not, is boundary lubrication sufficient? (remember that the bearing pressure is the load divided by the projected area normal to the load.)
2. [E11.7] A bronze statue weighing 4 tonnes with a base of area 0.8 mm2 is placed in a granite museum floor. The yield strength of the bronze is 240 MPa. What is the true area of contact, Ar, between the base and the floor?
3. [E11.8] The statue of the previous example was moved to a roof courtyard with a lead floor. The yield strength of the lead is 6 MPa. What now is the true area of contact?
4. A 200-tonne 747 is brought to rest from 200 kmph. How much is the heat energy generated? How much aluminium can be melted using the heat?
page revision: 2, last edited: 07 Apr 2009 06:31