Aball bearing is to be selected to withstand a radial load of 7500 n and have an lto life of 5 x 108 revolutions at a speed of 2000 rpm. the bearing maker's catalog rating sheets are based on an lio life of 6000 hrs at 1000 rpm. what load should be used to size the bearing in the catalog.

Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

At 12 noon, the count in a bacteria culture was 400; at 4: 00 pm the count was 1200 let p(t) denote the bacteria cou population growth law. find: (a) an expression for the bacteria count at any time t (b) the bacteria count at 10 am. (c) the time required for the bacteria count to reach 1800.