Shafting-Problems - IT is practice problem for board exam to help students PDF

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1. A round steel shaft transmits ¾ hp at 1,750 rpm.The shaft is subjected to torsion only and the design stress is 7,000 psi. Find the diameter.A. 0 in C. 0 in B. 0 in D. 0 in A 1-inch round steel shaft transmits 6 hp and rotates 200 rpm. If this shaft is subjected to pure torsion, what shearing str...

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1. A round steel shaft transmits ¾ hp at 1,750 rpm. The shaft is subjected to torsion only and the design stress is 7,000 psi. Find the diameter. A. 0.4384 in B. 0.8668 in

C. 0.2698 in D. 0.6326 in

2. A 1-inch round steel shaft transmits 6 hp and rotates 200 rpm. If this shaft is subjected to pure torsion, what shearing stress is induced? A. 9,625.69 psi B. 11,625.69 psi

C. 10,625.69 psi D. 8,625.69 psi

3. What is the gear running speed in a shaft 60 mm in diameter receiving from an engine 400 kW of power? A. 3,550 rpm B. 3,250 rpm

C. 3,760 rpm D. 3,460 rpm

4. A 7.5 MW gas turbine running at 4,500 rpm delivers power during peak load. What is the diameter of the transmission shaft? A. 143 mm B. 169 mm

C. 126 mm D. 180 mm

5. A transmission shaft has a torsional stress of 7,000 psi. If the diameter of shaft is 1.5 inches, what torque can be safely transmitted in lb-in? A. 4,638.77 B. 4,494.88

C. 4,266.66 D. 4,051.55

6. Determine the factor of safety needed for a 2-inch diameter shaft with an ultimate strength of 50,000 psi to transmit 40,000 in-lb of torque. A. 1.964 B. 2.346

C. 1.528 D. 2.705

7. What is the maximum torque in kN –m that can be applied to a hollow circular steel shaft of 120 mm outside diameter and 80 mm inside diameter without exceeding a shearing stress of 80 MPa? A. 23.46 C. 25.23 B. 27.95 D. 21.78 8. What is the polar section modulus of a 4-inches solid shaft?

A. 25.13 in3 B. 12.57 in3

C. 12.57 in4 D. 25.13 in4

9. A round steel shaft transmits ½ hp at 1,800 rpm. The shear modulus of elasticity is 12,000,000 psi. The torsional deflection is not to exceed 1 degree in a length equal to 20 diameters. Find the shaft diameter. A. 0.404 in B. 0.257 in

C. 0.804 in D. 0.657 in

10. A round steel shaft rotates 200 rpm and is subjected to a torque of 2,000 in-lb. The allowable shearing stress is 6,000 psi, it is also subjected to a bending moment of 3,000 in-lb. The allowable tensile stress is 8,000 psi. Find the diameter. A. 1.614 in B. 5.444 in

C. 3.228 in D. 1.323 in

11. A 1-inch diameter shaft is to be replaced with a hollow shaft of the same material, weighing half as much, but equally strong in torsion. The outside diameter of the hollow shaft is to be 1 ½ inches. Find the inside diameter. A. 3.646 inches B. 5.423 inches

C. 7.282 inches D. 1.323 inches

12. A shaft rotates 1,000 rpm and transmits ¾ hp. The shaft is subjected to torsion only and the working stress is to be 6,000 psi. Find the diameter. A. 0.5846 inch B. 0.1682 inch

C. 0.3423 inch D. 0.7264 inch

13. Find the diameter of the shaft (based on torsional stiffness) for which the angle of twist is not to exceed 1 degree in 20 diameters. The shaft transmits 5 hp and rotates 100 rpm. The modus of elasticity (shear) is 12,000,000 psi and the modus of elasticity (tension) is 30,000,000 psi. A. 7.8048 inches B. 1.4524 inches

C. 3.6286 inches D. 5.2462 inches

14. A solid shaft is subjected to a bending moment of 60,000 lb-in and a torque of 100,000 lb-in. The allowable shearing stress is 6,000 psi and the allowable tensile stress is 8,000 psi. Find its diameter.

A. 6.646 inches B. 2.288 inches

C. 4.827 inches D. 8.465 inches

15. A shaft supported on bearing 8 inches apart transmits 250 hp at 200 rpm. The maximum bending moment is 24,000 lb-in. The allowable shearing stress is 8,000 psi and the allowable bending stress is 7,000 psi because of unusual loading conditions. Find the shaft diameter. A. 2.422 inches B. 6.843 inches

C. 4.261 inches D. 8.686 inches

16. A ¼-inch shaft is designed with a working stress of 7,000 psi in shear. If it rotates at 1,725 rpm and the shear modulus of elasticity is 12,000,000 psi, what the torsional deflection in degrees per foot of length? A. 1.423 B. 4.623

C. 2.846 D. 3.2086

17. Compute for the polar section modulus of an SAE 1060 shafting having a diameter of 3 inches. Use a factor of safety of 2 and design stress at 8,000 psi. A. 4.7 in3 B. 4.2 in3

C. 6.1 in3 D. 5.3 in3

18. Two short shafts having identical diameter of 38.1 mm and rotating at 400 rpm are connected by a flange coupling. What is the torque transmitted by the short shaft in kN–m? A. 0.433 B. 0.633

C. 0.833 D. 0.233

19. A line shaft with a power of 100 kW at a speed of 1,200 rpm had a rectangular key used in it for pulley connection. Consider the shearing stress of the shaft to be 40 N/mm2 and the key to be 200 N/mm2. Find the shaft diameter in mm. A. 46.62 B. 50.62

C. 42.66 D. 38.66

20. A steel shaft is transmitting 50 hp at 1,200 rpm. The nature of the load and type of service of the shaft in such that the allowable shearing stress based on pure torsion is 4,000 psi. Calculate the torsional deflection of the shaft in degree per foot of the shaft.

A. 0.259⁰ B. 0.549⁰

C. 0.32⁰ D. 0.559⁰

21. A 76 mm solid shaft is to be replaced with a hollow shaft of equal torsional strength. Find the percentage of the weight saved, if the outside diameter of the hollow shaft is 100 mm. A. 46.56% B. 76.56%

C. 66.56% D. 56.56%

22. A centrifugal pump is directly coupled to a motor. The pump rating is 3,600 liters per minute against a total head of 8 m of water. Pump efficiency is 65% at shaft speed of 550 rpm. Calculate the torsional stress induced on the 40 mm diameter motor shaft in kPa. A. 8,000 B. 10,000

C. 9,000 D. 11,000

23. Determine the diameter in inches of steel countershaft that delivers 13.31 hp at a speed of 15.7 rad/sec, the allowable material shear stress is 8.5 ksi. A. 1-inch B. 2 inches

C. 1 ½ inches D. 1 ¼ inches

24. Determine the shaft diameter which is driven at 3,600 rpm by a 400 hp motor, if allowable torsional deflection is 1⁰, and the modulus of rigidity is 13x106 lb/in2. A. 2.85 inches B. 3.85 inches

C. 1.85 inches D. 4.85 inches

25. Compute for the torsional deflection in degrees of a 110 mm diameter, 1.4 m long shaft subjected to a twisting moment of 3 x 10 6 N-mm. The torsional modulus of elasticity is 83,000 N/mm 2. A. 0.27 B. 0.20

C. 0.31 D. 0.24

26. Determine the safe horsepower that can be transmitted by a 12 ft steel transmission shafting running at 250 rpm. Consider the bending action is caused only by its own weight. Consider that the torsional deflection will not exceed 0.08⁰/ft length. A. 12

C. 9.75

B. 3.25

D. 6.5

27. Determine the diameter of 12 ft long steel line shaft which is subjected to a bending action due to its own weight only. A. 4.271 inches B. 2.006 inches

C. 1.553 inches D. 3.012inches

28. Find the diameter in inches of the steel shaft transmitting 40 hp at 200 rpm. Let the torsional deflection will not exceed one degree in a length of 20 diameters. Assume the shear modulus of elasticity to be 12 x 10 6 psi. A. 2.3 B. 6.2

C. 4.6 D. 8.4

29. The transmitted torque of a 100 mm steel shaft is 5 kN-m and the maximum bending moment is 3 kN-m. Determine the allowable flexural or bending stress caused by the load of the pulley. A. 24.175 MPa B. 64.451 MPa

C. 44.976 MPa D. 84.326 MPa

30. A shaft is subjected to a 30,000 lb-in twisting moment with a shearing stress of 8,000 psi. What is the diameter of the shaft in inches? A. 2.67 inches B. 3 inches

C. 2.75 inches D. 3.25inches

31. Determine the diameter of a shaft in inches that rotates 100 rpm and transmit 1.2 hp. The design stress for shear is 6,000 psi and subjected to a pure torsion. A. 7/8-inch B. ¾ inch

C. ½ inch D. 1 inch

32. A solid steel shaft is needed by a 2.5 kW engine rotating at 1,200 rpm. Find the minimum shaft diameter in mm, if the allowable shear stress is 40 MPa. A. 11.6 mm B. 13.6 mm

C. 15.6 mm D. 9.6 mm

33. A line shaft transmits 200 hp at 900 rpm. Determine the diameter of the shaft. A. 2 3/8”

C. 2 1/8”

B. 2 5/8”

D. 2 ½”

34. A 2-inch line shaft is transmitting 20 hp rotating at 200 rpm, carrying two pulleys spaced 30 inches apart which can cause a torsional deflection on it. If the shear modulus of elasticity is 12,000,000 psi, find the angle of twist in degrees. A. 0.573⁰ B. 0.75⁰

C. 1⁰ D. 0.25⁰

35. Determine the diameter of a shaft in inches for which a torsional deflection will not exceed 1⁰ in a length of 20 diameters. The shaft is to transmit 40 hp running at 200 rpm. Assume that the shear modulus of elasticity is 12,000,000 psi. A. 3.31 inches B. 2.31 inches

C. 4.62 inches D. 5.62 inches

36. The torsional deformation of a steel shaft is to be 1⁰ in a length of 600 mm. The design shear stress is equal to 69 MPa. Determine the diameter of the shaft in mm and consider a shear modulus of elasticity of 79,300 MPa. A. 55.42 mm B. 63.68 mm

C. 59.84 mm D. 67.26 mm

37. A 1-inch solid shaft is to be replaced with a hollow shaft of equal torsional strength having an outside diameter of 2 inches. Determine the inside diameter of the replacement shaft in inches. A. 1 3/4 inches C. 2 1/2 inches B. 2 1/4 inches D. 2 inches 38. A 1-inch solid shaft is to be replaced with a hollow shaft equal torsional strength having an outside diameter of 2 inches. Determine the percentage of weight saved. A. 72.5% B. 76.3%

C. 74.2% D. 70.4%

39. A solid transmission shaft is 88.9 mm diameter. It is desired to replace it with a hollow shaft of the same material and same torsional strength but its weight should only be half as much as the solid shaft. Find the outside diameter and inside diameter of the hollow shaft in mm. A. 76.175 & 38.2

C. 107.31 & 86.97

B. 66.175 & 28.2

D. 86.175 & 48.20

40. A shaft transmits 10 hp at 500 rpm. Assume that the design stresses are 6,000 psi (shear) and 8,000 psi (tension) and the shaft is subject to a bending moment of 3,000 in-lb. Compute the diameter of the shaft in inches. A. 1.4 inches (bear on (based on bending) B. 1.2 inches (bear on (based on bending) C. 8.0 inches (bear on (based on bending) D. 1.6 inches (bear on (based on bending)

shear); 1.59 inches shear); 1.33 inches shear); 1.99 inches shear); 1.79 inches

41. A line shaft is to transmit 200 hp at 900 rpm. If the line shaft is connected to a 2” counter shaft with speed of 1,600 rpm, determine the hp transmitted. A. 327 hp B. 347 hp

C. 337 hp D. 357 hp

42. A shaft is subjected to a constant torque of 2,260 kN-m. The ultimate strength and yield strength of the shafting material are 668 MPa and 400 MPa, respectively. Assume a factor of safety of 2 based on yield and endurance strength in shear. Determine the diameter of the shaft. A. 7.2” B. 12.2”

C. 15.2” D. 19.2”

43. A 2-inch diameter solid shaft has a maximum bending moment of 6,000 in- lb and an applied torque of 3,000 in-lb. Compute the equivalent bending moment. A. 12,708.2 in-lb B. 3.177.2 in-lb

C. 9.531.1 in-lb D. 6,354.1 in-lb

44. A 48-inch diameter saw blade is mounted on a pulley driven steel shaft; the required blade peripheral linear speed is 150 fps. Motor drive is 25 hp running at 1,200 rpm with a 6 inches diameter pulley. Determine the shaft rpm to attain the blade peripheral speed required. A. 716.2 B. 761.2

C. 617.2 D. 671.2

45. A 48-inch diameter saw blade is mounted on a pulley driven steel shaft; the required blade peripheral linear speed is 150 fps. Motor driven is 25 hp running at 1,200 rpm with a 6 inches diameter pulley. Determine the diameter of the shaft the motor requires. A. 3.162” B. 1.186”

C. 2.106” D. 4.153”

46. A 48-inch diameter saw blade is mounted on a pulley driven steel shaft, the required blade peripheral linear speed is 150 fps. Motor drive is 25 hp running at 1,200 rpm with a 6 inches diameter pulley Determine the diameter of the pulley driving the steel shaft. A. 8.206” B. 10.053”

C. 6.409” D. 4.605”

47. A hollow shaft carries a torque 3.4 kN-m at a shearing stress of 55 MPa. The outside diameter is 1.25 times that of the inside diameter. Determine the inside diameter in mm. A. 64.87 B. 84.67

C. 46.87 D. 74.64

48. A hollow shaft has an inner diameter of 0.053 m and an outer diameter of 0.06 m. Compute for the torque in kN–m, if the shear stress is not to exceed 120 GPA. A. 4,880.8 kN –m B. 1,770.8 kN–m

C. 1,990.8 kN–m D. 4,500.8 kN–m

49. A round steel shaft transmits 0.75 hp at 1,750 rpm. The shaft is subjected to torsion only and the design stress is 7,000 psi. Determine the diameter of the shaft. A. 0.27 inch B. 0.74 inch

C. 0.37 inch D. 0.57 inch

50. Design the size of solid steel shaft to be used for a 500 hp, 250 rpm application if the allowable torsional deflection is 1⁰ per foot and the allowable stress is 10,000 psi and modulus of rigidity is 13 x 106 psi. A. 1.004 inches B. 4.004 inches

C. 2.004 inches D. 3.004 inches

51. A round steel shaft rotates at 200 rpm and is subjected to a torque at 275 N–m and a bending moment of 415 N –m. Determine the equivalent twisting moment (N-m) and the equivalent bending moment (N-m). A. 597.84 & 546.42 B. 456.42 & 497.85

C. 546.42 & 597.84 D. 497.85 & 456.42

52. A shaft supported on bearings 200 mm apart transmits 187 kW at 200 rpm. The maximum bending moment is 2,712 N–m. The allowable shearing stress is 53.3 MPa and the allowable bending stress is 46.7 MPa because of the unusual loading. Determine the shaft diameter in mm. A. 96.2 B. 102.5

C. 109.5 D. 117.52...