ASCENDO ENGINEERING REVIEW CENTER

MD - PROBLEM SET # 3
INSTRUCTION: Encircle the letter that corresponds to the correct answer of your choice.

1. Determine the permissible working stress of a UNC bolts that has a stress area of 0.606 in2 if material used
in carbon steel.
A. 4055.5 psi B. 5244.5 psi C. 4675.5 psi D. 4186.5 psi

2. The stress area of UNC bolt is 0.763 in2, if material used is carbon steel, determine te applied load on the bolt.
A. 3407.14 lbs. B. 3846.71 lbs. C. 4025.86 lbs. D. 3102.74 lbs.

3. Compute the working strength of 1 1/2 in. bolt which is screwed up tightly in packed joint when the
allowance working stress is 13,000 psi.
A. 11,465.5 lbs. B. 13,860.5 lbs. C. 11,212.5 lbs. D. 11,854.5 lbs.

4. Determine the diameter of bolt needed to tightly pack the joint. Bolt working strength is 90.76 KN and
working stress is 82.71 Mpa.
A. 0.5 in. B. 1.0 in. C. 1.5 in. D. 2.0 in.

5. A 12 cm x 16 cm air compressor have 5 bolts on cylinder head with yield stress of 440 Mpa. If the bolt
stress area is 0.13 in2, determine the maximum pressure inside the cylinder.
A. 142.23 psi B. 671.96 psi C. 742.78 psi D. 840.60 psi

6. The cylinder head of ammonia compressor has core gasket are of 80 cm2 and flange pressure of 90 kg/cm2.
Determine the torque applied on the bolt if nominal diameter of bolt used is 3/5 inch and there are 5
bolts.
A. 476.28 in.lb B. 586.28 in.lb C. 381.02 in.lb D. 666.28 in.lb

7. The total torque required to turn the power screw is 50 N.m. If the linear speed of screw is 7 ft./min and
lead of 8mm, find the horsepower input of the power screw.
A. 2.86 hp B. 1.84 hp C. 2.14 hp D. 2.38 hp

8. A single square thread power screw has a lead of 6 mm and mean diameter of 34 mm. If it is used to lift a
load of 26 KN and coefficient of friction of thread is 0.15, determine the torque required to turn the screw.
A. 91.9 N.m B. 65.8 N.m C. 72.6 N.m D. 86.5 N.m

9. An acme thread power screw that has a mean diameter of 25 mm and pitch of 5 mm is used to lift a load of
500 kg. If friction on threads is 0.1, determine the torque needed to turn the screw.
A. 11.10 N.m B. 126.3 N.m C. 13.10 N.m D. 10.30 N.m

10. A double square thread power screw has a mean radius of 80 mm and a pitch of 10 mm is used to lift a load
of 80 KN. If friction of screw is 0.13 and collar torque is 20% of input torque, determine the input torque
required.
A. 830.75 N.m B. 1365.40 N.m C. 840.76 N.m D. 846.76 N.m

11. The root diameter of a double square thread power screw is 0.55 in. The screw has a pitch of 0.2 in.
Determine the major diameter.
A. 0.524 in. B. 0.750 in. C. 0.842 in. D. 0.961 in.

12. A power screw consumes 6 hp in raising a 2800 lb weight at the rate of 30 ft/min. Determine the efficiency of
 the screw.
A. 12.5% B. 16.8% C. 42.42% D. 66.62%

13. A square thread power screw has a pitch diameter of 1.5 and a lead of 1 in. Neglecting collar friction,
determine the coefficient of friction for threads if screw efficiency is 63.62%
A. 0.113 B. 0.121 C. 0.146 D. 0.151

14. A square thread screw has an efficiency of 70% when friction of threads is 0.10 and collar friction is
negligible. Determine the lead angle.
A. 12.6 B. 14.3 C. 16.5 D. 18.3

15. A 12 cm x 16 cm air compressor is operating with a maximum pressure of 10 kg/cm2. There are 5 bolts
which held the cylinder head to the compressor. What is the maximum load per bolt in KN?
A. 2.22 B. 4.44 C. 3.33 D. 5.55

16. What weight can be lifted by a screw that has an efficiency of 80% if it is operated by a 50 lb force at the end
of a 30 in lever? The pitch diameter of the screw is ½ in.
A. 12,000 lbs B. 13,000 lbs C. 14,000 lbs D. 15,000 lbs

17. Find the horsepower lost when a collar is loaded with 1000 lb, rotates at 25 rpm, and has a coefficient of
friction of 0.15. The outside diameter of the collar is 4 inches and inside diameter is 2 inches.
A. 0.0629 Hp B. 0.0926 Hp C. 0.0269 Hp D. 0.0692 Hp

18. Compute the working strength of 1” bolt which is screwed up tightly in a packed joint when the allowable
working stress is 13,000 psi.
A. 3600 lbs B. 3950 lbs C. 3900 lbs D. 3800 lbs

19. What is the working strength of 2” bolt which is screwed up tightly in packed joint when the allowable
working stress is 12,000 psi?
A. 20,120 lbs B. 20,400 lbs C. 20,400 lbs D. 20,200 lbs

20. What is the frictional HP acting on a collar loaded with 100 kg weight? The collar has an outside diameter of
100 mm and an internal diameter of 40 mm. The collar rotates at 1000 rpm and the coefficient of friction
between the collar and the pivot surface is 0.15.
A. 0.8 HP B. 0.5 HP C. 0.3 HP D. 1.2 HP

21. If the pitch of a screw is 2/9, find the thread per inch.
A. 0.34 B. 4.5 C. 5.4 D. 17

22. An eyebolt is lifting a block weighing 350 lbs. The eyebolt is of SAE 1040 material with Su = 67 ksi and Sy = 55
ksi what is the stress area (in inches square) of the bolt if it is under the unified coarse series thread?
A. 1341 B. 0.1134 C. 0991 D. 1043

23. Compute how many 3/8-inch diameter set screws required to transmit 3 Hp at a shaft speed of 1000 rpm.
The shaft diameter is 1 inch.
A. 1 ½ B. 2 C. 3 D. 1

24. For a bolted connection, specification suggests that a high-grade material of 13 mm bolt be tightened to an
initial tension of 55,000 N. What is the appropriate tightening torque?
A. 41 N-m B. 139 N-m C. 145 N-m D. 143 N-m
25. An eye bolt is lifting 500 lbs weight. The Su = 70 ksi and Sy = 58 ksi. What is the stress area of the bolt?
A. 0.009 in2 B. 0.026 in2 C. 0.1388 in2 D. 0.1276 in2
26. Find the horsepower required to drive a power screw lifting a load of 4000 lbs. A 2 and ½ inches double
square thread with two threads/inch is to be used. The frictional radius of the collar is 2 inches and the
coefficients of friction are 0.10 for the threads and 0.15 for the collar. The velocity of the nut is 10 ft/min.
A. 5.382 HP B. 4.383 HP C. 3.683 HP D. 6.472 HP

27. Determine the diameter of the stud bolt that are required to fasten down the cylinder head of a 203 mm x
304 mm gas engine. There are ten bolts on the block. The explosion pressure is 31 kg/sq cm and studs are
made of ordinary bolts material SAE 1020. How deep should the bolt be drilled?
A. 38.1 mm B. 40.2 mm C. 37.3 mm D. 35.5 mm

28. A double thread Acme screw driven by a motor at 400 rpm raises the attached load of 900 kg at a speed of
10 meters per minute. The screw has a pitch diameter36 mm. The coefficient of friction on threads is 0.15.
The friction torque on the thrust bearing of the motor is taken as 20% of the total torque input. Determine
the motor power required to operate the screw.
A. 3.239 KW B. 4.658 KW C. 2.482 KW D. 4.391 KW

29. A 12 cm x 16 cm air compressor is operating with a maximum pressure of 10 kg/cm2 which held the cylinder
head to the compressor. The core gasket area is 60 cm2 with a flange pressure of 100 kg/cm2. Determine
the size of UNF bolts in inches.
A. ½ in B. ¼ in C. 1/3 in D. ½.5 in

30. The root diameter of a double square thread is 0.55 inch. The screw has a pitch of 0.20 inch. Find the
outside diameter and the number of threads per inch.
A. 0.75 inch and 5 threads/inch B. 0.50 inch and 5 threads/inch
C. 0.75 inch and 4 threads/inch D. 0.50 inch and 4 threads/inch

31. A single square thread power screw is to raised load of 70 KN. The screw has a major diameter of 36 mm and
a pitch of 6 mm. The coefficient of thread friction and the collar friction are 0.13 and 0.10 respectively. If the
collar mean diameter is 90 mm, and the screw turns at 60 rpm, find the combined efficiency of screw and
collar.
A. 13.438% B. 15.530% C. 14.526% D. 12.526%

32. A single threaded trapezoidal metric thread has a pitch of 4 mm, and a mean diameter of 18 mm. It is used as
a translation screw in conjunction with a collar having an outside diameter of 37 mm and an inside diameter
of 27
mm. Find the required torque in N-m to raise a load of 400 kg if the coefficient of friction is 0.3 for both
threads and collar.
A. 34.6 N-m B. 32.6 N-m C. 39.1 N-m D. 38.5 N-m

33. The collar of the capstan has an outside diameter of 8 in and an inside diameter of 6 in. The total load support
is 2000 lbs. If the coefficient of friction is 0.10, what is the collar friction torque?
A. 705 in-lb B. 802 in-lb C. 1012 in-lb D. 972 in-lb

34. Calculate the bolt area in mm2 of each of 20-bolts used to fasten the hemispherical joints of a 580 mm
pressure vessel with an internal pressure of 10 MPa and a material strength of 80 MPa and a bolt strength of
150 MPa:
A. 880.69 B. 920.5 C. 820 D. 790

35. A double-thread Acme-form power screw of 50 mm major diameter is used. The nut makes 1 turn per cm of
axial travel. A force of 60 kg is applied at the end of a 750 mm wrench used on the nut. The mean diameter
of the collar is 90 mm. If the coefficient of friction at the thread and at the collar are 0.15 and 0.13,
respectively. Determine the weight that is being lifted.
A. 42.95 KN B. 39.50 KN C. 45.82 KN D. 32.72 KN
36. Determine the stress area in in2 of a 1-8UNC bolt.
A. 0.563 in2 B. 0.606 in2 C. 0.334 in2 D. 0.785 in2

37. Determine the stress in psi of a 1-4UNC bolt if applied force is 4000 lb.
A. 4991 psi B. 5991 psi C. 6991 psi D. 8901 psi

38. A squared and ground ends spring has a pitch of 20 mm, wire diameter of 12.5 mm. If there are 12
actual number of coils the deflection when spring is compressed to its solid length.
A. 78 mm B. 75 mm C. 77 mm D. 79 mm

39. A spring with plain ends has 15 active coils diameter of 6 mm and pitch of 10 mm. If spring rate is 100
KN/m, determine the solid force.
A. 4 KN B. 5 KN C. 6 KN D. 7 KN

40. A spring rate has a spring rate of 30 KN/m. If wire diameter is 10mm with a mean diameter of 70 mm,
determine the number of active coils. G = 80 GN/m2.
A. 6.54 B. 7.82 C. 8.42 D. 9.72

41. A spring has a load of 50 lb. with a spring index of 8. If stress induced is 90,000 psi, determine the
wire diameter.
A. 0.058 in. B. 0.828 in. C. 0.452 in. D. 0.1157 in.

42. It is found that a load of 50 lb. an extension coil spring deflects 8.5 in. What load deflect the spring 2.5 in?
A. 10.64 lb. B. 12.48 lb. C. 13.48 lb. D. 14.70 lb.

43. A spring sustain 200 ft-lb of energy with deflection of 3 in. Assume that the main coil diameter is 7 times the
wire diameter and allowable stress of 100,000 psi, determine the wire diameter.
A. 0.416 in. B. 0.321 in. C. 0.568 in. D. 0.672 in.

44. A weight of 100 lbs. strikes a coil spring from a height of 18 inches and deflects the spring of 6 inches. Find the
average force acting on the spring.
A. 600 lb. B. 700 lb. C. 800 lb. D. 900 lb.

45. If it is determined experimentally that a load of 20 kg applied to an extension coil spring will provide a
deflection of 200 mm. What load will deflect the spring 60 mm.
A. 4 kg B. 5 kg C. 6 kg D. 7 kg

46. Three extension coil spring are hooked in series and supports a weight of 70 kg. One spring has a spring rate of
0.209 kg/mm. and the other two have spring rates of 0.643 kg/mm. Find the deflection.
A. 346.71 mm B. 389.30 mm C. 426.71 mm D. 552.66 mm

47. Four compression coil spring in parallel support a load of 360 kg. Each spring has a gradient of 0.717 kg/mm.
A. 125.52 mm B. 132.52 mm C. 138.52 mm D. 145.52 mm

48. A spring has a diameter of 25 mm and 12 active coils. If a load of a 10 KN is applied, it deflects 75 mm.
Determine the mean diameter of the spring G = 80 GN/m2.
A. 20 mm B. 134.65 mm C. 150.34 mm D. 40 mm

49. All four-compression coil spring support one load of 400 kg. All four springs are arranged in parallel and rated
same at 0.709 kg/mm. Compute the deflection in mm.
A. 564 B. 1457 C. 171 D. 141

50. A force of 1.1 KN is acting on a 7.5 active coils with wire diameter of 13 mm. The outside diameter of coil is 117
mm and G = 80 GN/m2. Determine the deflection.
A. 27.6 mm B. 29.8 mm C. 32.5 mm D. 34.6 mm
ANSWER KEY:
1. A 15. A 29. A 43. C
2. A 16. D 30. A 44. C
3. C 17. B 31. D 45. C
4. D 18. C 32. B 46. D
5. A 19. C 33. A 47. A
6. C 20. A 34. A 48. B
7. B 21. B 35. B 49. D
8. A 22. B 36. B 50. C
9. D 23. B 37. D
10. B 24. D 38. B
11. B 25. C 39. C
12. C 26. B 40. D
13. A 27. A 41. D
14. B 28. A 42. D