What should be the outside diameter of this disk brake?

1.A disk brake is to be constructed for use on a highspeed rotor balancing machine. It has been decided that a carbon-graphite friction material will be used against a steeldisk mating surface to provide the braking action. The environment is dry. For clearance reasons the inner diameter of the steel brake disk must be 10.0 inches and its thickness is 0.375 inch. Further, the brake must be able to absorb 2.5 106 in-lb of kinetic energy in one-half revolution of the disk brake as it brings the high-speed rotor to a full stop. Only one braking surface can be used.

a. What should be the outside diameter of this disk brake?

b. What axial normal actuating force will be required for the brake to function properly?

c. Due to the short stopping time, it is estimated that only about 10 percent of the volume of the steel disk constitutes the entire “effective” heat sink for the brake. About how large a temperature rise would you expect in this brake during the stop? Is this acceptable?