WORLD FOR CIVIL

Statics & Strength of Materials

Topic 6.4b - Problem Assignment 2 - Torsion

1. An outboard motor has a steel shaft 1/2 inch in diameter and 18 inches long. It develops a torque of 75 inch pounds at 6000 rpm. Determine the horse power that is developed. G = 12x10⁶ psi. (7.14 hp)

2. A quarter horsepower electric drill turns at 750 rpm. What is the torque that is developed in the drill bits? (1.75 ft-lb)

3. The drive shaft of a car has a torque applied of 1600 inch pounds. The drive shaft is 4 feet long and 2.5 inches in diameter with a 1/16 diameter wall thickness. Determine the power delivered by the shaft when the angular speed of the shaft is 1500 rpm.(38.1 hp)

4. A motorcycle is shaft driven with a 1 inch solid steel shaft. The maximum allowable transverse shear stress in the shaft is 8,000 psi. Determine the maximum power that can be delivered by the shaft if it is rotating at 6000 rpm. What is the angle of twist of the shaft if the shaft is 24 inches long. (150 hp, .032 rad)

5. The propeller on an ship has a 72 inch pitch and turns at 180 rpm. The shaft on the propeller transmits 3000 horse power. Determine the minimum polar moment of inertia of the shaft if the shaft steel has a maximum allowable shear stress of 12,000 psi. What is the required diameter of the shaft if it is solid?
(334.5 in⁴, 7.64 in.)