Mechanical Engineering Review Online

1. A helical gear tangential load of 220 lbs and axial load of 75 lbs. Compute the helix angle.

a. 30.33 deg

b. 70.07 deg

c. 65.31 deg

d. 75.81 deg

2. A helical gear having 22 teeth and pitch diameter of 6-in. Find the normal diametral pitch if the helix angle is 20 degrees.

a. 4.28

b. 2.87

c. 3.90

d. 5.38

3. An 80 HP motor, running at 460 rpm is geared to a pump by means of helical gear having a pinion diameter of 9-in. Find the tangential force of the gear.

a. 1587.82 lbs

b. 2435.76 lbs

c. 3055.27 lbs

d. 1870.31 lbs

4. A helical gear having a helix angle of 22 degrees and pressure angle of 20 degrees, find the pressure angle normal to the teeth.

a. 16.32 deg

b. 18.65 deg

c. 22.75 deg

d. 25.18 deg

5. A 30-tooth helical gear having a pitch diameter of 8 has a helix angle of 23 degrees. Find the circular pitch in a plane normal to the teeth.

a. 0.7712

b.0.6287

c. 0.3211

d. 0.8717

6. A 20-tooth helical gear has a pitch diameter of 10-in. Find the diametral pitch of the gear.

a. 2

b. 3

c. 4

d. 5

A worm has four threads of 14.5 deg normal pressure angle and pitch diameter of 5.25-in. The gear has 56 teeth of 1.75-in pitch.

7. Find the efficiency of the worm if the friction is 0.030.

a. 90.23%

b. 85.21%

c. 88.71%

d. 92.17%

8. Find the center distance of the shafts

a. 16.22 in

b. 18.22 in

c. 14.22 in

d. 20.22 in

9. A triple thread worm gear has normal pressure angle of 14.5 deg and coefficient of friction of 0.20. If the worm efficiency is 78%, find the lead angle.

a. 83%

b. 70%

c. 78%

d. 74%

10. A triple thread worm gear has a pitch of 3/4-in and pitch diameter of 3-in. The normal pressure angle is 14.5 degrees and coefficient of friction is 0.12. Find the worm efficiency.

a. 56%

b. 60%

c. 68%

d. 64%

11. A triple thread worm gear having a diametral pitch of 5-in is used to deliver a gear. The speed ratio is 8. Find the pitch line velocity of gear if the worm rotates at 650 rpm.

a. 2.11 fps

b. 3.28 fps

c. 4.11 fps

d. 1.70 fps

12. A double thread worm has a helix angle of 83 deg and pitch diameter of 5.75-in. The worm rotates at 820 rpm. Find the linear speed of the worm.

a. 151.56 fpm

b. 168.71 fpm

c. 173.11 fpm

d. 187.8 fpm

13. A triple thread worm gear is used to drive a 24 teeth gear having a pitch of 0.75-in. Compute the center distance.

a. 2.22 in

b. 3.22 in

c. 4.23 in

d. 5.36 in

14. A double thread worm having a pitch of 1-in is used to drive a 42 teeth gear. Find the pitch diameter of the gear.

a. 10.21 in

b. 12.18 in

c. 13.37 in

d. 16.55 in

15. A triple-thread worm, rotating at 1,200 rpm, drives 32-teeth gear. Find the speed of the gear.

a. 98.2 rpm

b. 112.5 rpm

c. 120.1 rpm

d. 135.8 rpm

16. A triple-thread worm gear has pitch of 0.75-in and pitch diameter of 3.75-in. Find the helix angle.

a. 75.2 deg

b. 79.2 deg

c. 70.2 deg

d. 85.8 deg

17. A triple-thread worm gear has a helix angle of 82 degrees. It has a pitch of 3/4-in. Find the pitch diameter of the worm.

a. 4 in

b. 5 in

c. 6 in

d. 7 in

18. A double-thread worm gear has a lead angle of 6.0 deg and pitch radius of 2.25-in. Find the pitch of the worm.

a. ¾ in

b. ½ in

c. 1/8 in

d. ¼ in

19. A work rotating at 1200 rpm drives a worm gear. The velocity ratio is 16 to 1. A 12 HP motor is used to supply the worm with worm pitch gear diameter of 3.5-in. Find the tangential force on the worm.

a. 450 lbs

b. 500 lbs

c. 400 lbs

d. 550 lbs

20. A pair of bevel gear having a speed ratio of 2 has a 4-pitch at 14.5 deg involute. The pitch diameter of pinion is 8-in. Find the dedendum angle of the gear.

a. 2.5 deg

b. 3.8 deg

c. 4.7 deg

d. 1.8 deg

21. A pair of bevel gear having a speed ratio of 4 has a 5-pitch at 14.5 deg involute. The pitch diameter of the pinion is 7-in. Find the addendum angle of the pinion (at right angle between shafts).

a. 4.1 deg

b. 3.2 deg

c. 2.8 deg

d. 1.1 deg

22. The cone angle of pinion and the gear are 24 deg and 64 deg, respectively, find the speed ratio.

a. 3.21

b. 4.32

c. 2.21

d. 5.11

23. The cone angle of pinion of a pair of bevel gear is 32 deg while for the gear is 64 deg. If the pinion turns 280 rpm, find the speed of the gear.

a. 165.1 rpm

b. 174.9 rpm

c. 185.2 rpm

d. 148.2 rpm

24. A spiral bevel pinion with a left hand spiral transmits 5 HP at 1300 rpm to a mating gear. The mean diameter of the pinion is 4-in. Find the tangential force at the mean radius of the gear.

a. 110.2 lbs

b. 135.8 lbs

c. 121.2 lbs

d. 140.8 lbs

25. A spiral bevel pinion with a left hand spiral rotates clockwise transmits power to a mating gear with speed ratio of 3.0 to 1. Determine the pitch angle of the pinion.

a. 15.4 deg

b. 16.5 deg

c. 12.3 deg

d. 18.4 deg

26. A pair of straight tooth bevel gear connects a pair of shafts at 90 deg. The velocity ratio is 2 to 1. What is the cone pitch angle of smaller gear?

a. 26.56 deg

b. 30.50 deg

c. 24.88 deg

d. 22.57 deg

27. A straight tooth bevel gear has a face width of 5-in and a pitch diameter of 15-in with cone pitch angle of 40 deg. If the torque on the gear is 8200 in-lb, what is the tangential force on the gear?

a. 2317.5 lbs

b. 1391.5 deg

c. 1879.5 deg

d. 2011.1 deg

28. A 20 deg full depth straight tooth gear has a face width of 3.75-in and a pitch diameter of 13-in with cone pitch angle of 38 deg. Find the mean diameter.

a. 8.7 in

b. 10.7 in

c. 12.8 in

d. 14.6 in

Answer Key (Handwritten)