MD P3 EXAMINATION ANSWER KEY (GEARS)
1. C
2. A
3. D
4. C
5. C
6. D
7. B
8. B
9. A
10. D
11. A
12. A
13. C
14. D
15. B
16. D
17. A
18. C
19. B
20. C
21. C
22. B
23. C
24. A
25. B
26. A
27. C
28. C
29. D
30. A
31. A
32. B
33. D
34. B
35. B
36. B
37. C
38. C
39. D
40. B
41. B
42. A
43. C
44. C
45. C
1) A standard 20 degrees full-depth spur gear has 24 teeth and a circular pitch of 0.7854 in.
Determine the working depth.
a. 0.25 in
b. 0.33 in
c. 0.50 in
d. 0.60 in
2) The cone angle of pinion of a pair of bevel gear is 30 deg while for the gear 60 deg. If the pinion
turns at 300 rpm, find the speed of the gear.
a. 173.211 rpm
b. 183.21 rpm
c. 193.21 rpm
d. 203.21 rpm
3) The cone angle of pinion and gear are 25 deg and 65 deg respectively. Find the speed ratio.
a. 1.5
b. 5.2
c. 4.23
d. 2.14
4) An internal gear has a center distance of 20 in. If speed ratio is 3, find the diameter of the
internal gear.
a. 18 in
b. 22 in
c. 20 in
d. 24 in
5) Find the clearance of a 14.5 deg involute gear having a module of 2.5.
a. 0.0534 in
b. 0.0246 in
c. 0.0154 in
d. 0.1345 in
6) What is the addendum of a gear having a module of 3?
a. 0.234 in
b. 0.198 in
c. 0.345 in
d. 0.118 in
7) Find the distance between centers of a pair of gears, one of which has 12 teeth and the other 37
teeth. The diametral pitch is 7.
a. 3.0 in
b. 3.5 in
c. 4.0 in
d. 4.5 in
8) A 10 inches diameter gear is use to transmit 20 kW at 900 rpm. Determine the tangential force
on each gear.
a. 1.761 kN
b. 1.671 kN
c. 1.842 kN
d. 2.614 kN
9) A triple thread worm has a pitch diameter of 3 inches. The wheel has 25 teeth and a pitch
diameter of 5 inches. Material for both the work and the wheel is of phosphor bronze. Compute
the helix angle.
a. 0.20
b. 0.30
c. 0.40
d. 14
10) A helical gear having a 14.5 degree normal pressure angle and transverse diametral pitch of
2.3622 per cm, the helix angle is at 45 deg and has 8 teeth. Compute the transverse pressure
angle in degrees.
a. 22.2 deg
b. 19.3 deg
c. 18.9 deg
d. 20.1 deg
11) Compute the pitch angle of a bevel gear given the pinion’s number of teeth of 14 and 42 teeth
on the gear.
a. 18.4 deg
b. 28.4 deg
c. 33.4 deg
d. 38.4 deg
12) Find the distance between centers of a pair of gears, one of which has 12 teeth and the other 48
teeth. The diametral pitch is 6.
a. 5.0 in
b. 4.0 in
c. 3.5 in
d. 4.5 in
13) Determine the pitch diameter of a gear with 36 teeth, 4 diametral pitch.
a. 7 in
b. 8 in
c. 9 in
d. 10 in
14) Two parallel shafts have an angular velocity ratio of 3 to 1 are connected by gears, the largest of
which has 51 teeth. Find the number of teeth of smaller gear.
a. 10
b. 13
c. 15
d. 17
15) A pair of meshing gears has a diametral pitch of 8, a center distance of 6 inches, and velocity
ratio of 1.6. Determine the number of teeth of smaller gear.
a. 12
b. 37
c. 24
d. 41
16) How many revolutions per minute is a spur gear turning at, if it has 20 teeth, a circular pitch of
0.7854 in and a pitch line velocity of 200 ft/sec?
a. 378.44 rpm
b. 954.66 rpm
c. 643.82 rpm
d. 763.94 rpm
17) A double thread worm has a helix angle of 80 deg and a pitch diameter of 4.5 in. The worm
rotates at 800 rpm. Find the linear speed of the worm.
a. 166.18 fpm
b. 139.82 fpm
c. 149.83 fpm
d. 159.82 fpm
18) The worm has four threads of 14.5 deg normal pressure angle and a pitch diameter of 4.25 in.
The gear has 64 teeth of 1.5 in pitch. Find the efficiency of the worm if friction is 0.03.
a. 82.88%
b. 86.88%
c. 92.25%
d. 94.25%
19) A 25-tooth helical gear has a pitch diameter of 10 in. Find the diametral pitch of the gear.
a. 2
b. 2.5
c. 3.0
d. 3.5
20) A 28-tooth helical gear having a pitch diameter of 7 in has a helix angle of 19˚. Find the circular
pitch in a plane normal to the teeth.
a. 0.528
b. 0.628
c. 0.743
d. 0.843
21) A 20˚ full depth straight tooth bevel gear has a face width of 3 ¾ in and a pitch diameter of 14 in
with a cone pitch angle of 37.5˚. Find the mean diameter.
a. 7.72 in
b. 9.72 in
c. 11.72 in
d. 13.72 in
22) A straight tooth bevel gear has a face width of 4 in and a pitch diameter of 14 in with cone pitch
angle of 35˚. If the torque on the gear is 8200 in-lb, what is the tangential force on the gear?
a. 1400 lbs
b. 1401 lbs
c. 1402 lbs
d. 1403 lbs
23) A pair of straight tooth bevel gear connect a pair of shafts 90˚. The velocity ratio is 4 to 1. What
is the cone pitch angle of smaller gear?
a. 71.57 deg
b. 65.34 deg
c. 14.04 deg
d. 12.34 deg
24) A worm rotating at 1150 rpm drives a worm gear. The velocity ratio is 10 to 1. A 12 Hp motor is
used to supply the worm with worm pitch gear diameter of 3 in. Find the tangential force on the
worm.
a. 438.43 lbs
b. 465.37 lbs
c. 565.37 lbs
d. 638.43 lbs
25) A triple thread worm gear is use to drive a 30-tooth gear having a pitch of ¾ in. Find the center
distance.
a. 2.34 in
b. 3.94 in
c. 4.34 in
d. 5.94 in
26) Type of gear that transmits power at an angle.
a. Bevel
b. Helix
c. Herringbone
d. Spur
27) A plane perpendicular to the gear axis.
a. Normal plane
b. Pitch plane
c. Plane of rotation
d. Radius of gyration
28) Circular pitch is measured along the _____ in the circular gear.
a. Circle
b. Line of action
c. Pitch center
d. Pitch diameter
29) The effective face width of a helical gear divided by the axial pitch. This is sometimes called face
overlap.
a. Angle overlap
b. Axial overlap
c. Contact overlap
d. Helical overlap
30) It is a plane between mating teeth or the amount of which a tooth space exceed the thickness of
an engaging tooth is called:
a. Backlash
b. Clearance
c. Pitting
d. Space
31) Plane of rotation is defined as plane perpendicular to a:
a. Gear axis
b. Gear ratio
c. Normal plane
d. Pitch diameter
32) Commonly used in parallel shaft transmission especially when a smooth continuous action is
essential as in high speed drives up to 12,000 fpm.
a. Bevel gear
b. Helical gear
c. Herringbone gear
d. Spur gear
33) The reciprocal of a diametral pitch or the ratio of the pitch diameter to the teeth.
a. Clearance
b. Involute
c. Lead
d. Module
34) Bevel gears of sizes 5 in to 15 in. should not be lift or depress more than ______ as gleason
statement.
a. 0.004
b. 0.003
c. 0.002
d. 0.001
35) A toothed wheel whose tooth elements are straight and parallel to the shaft axis or used to
transmit motion and power between parallel shafts.
a. Helical gear
b. Spur gear
c. Worm gear
d. Bevel gear
36) The distance from a point on one gear to the corresponding point measured along the base
circle.
a. Diametral pitch
b. Normal pitch
c. Circular pitch
d. Chordal pitch
37) Which of the following is a single measure that combines the external dynamic load of an
application with a gear drive’s reliability and operating life?
a. Ratio factor
b. Reliability factor
c. Service factor
d. Life factor
38) Which of the following is used to cut gears?
a. gear cutter
b. gear center
c. gear hob
d. gear threader
39) What is the actual torque ratio of a gear set divided by its gear ration?
a. approach ratio
b. clearance
c. contact ratio
d. efficiency
40) It is used to change rotary motion to reciprocating motion:
a. Helical gear
b. Rack gear
c. Worm gear
d. Spur gear
41) The distance of the tooth, which is equal to the sum of the addendum and dedendum:
a. Full depth
b. Whole depth
c. Working depth
d. Dedendum
42) The concave portion of the tooth profile where it joints the bottom of the tooth space:
a. Fillet curve
b. Fillet radius
c. Bottom depth
d. Fillet
43) In gear design, the ratio of the pitch diameter in inches to the number of teeth:
a. Module
b. Diametral pitch
c. English module
d. Circular pitch
44) Gear used to transmit power to high velocity ratios between non-intersecting shafts that are
usually but not necessarily at right angle.
a. Helical gear
b. Bevel gear
c. Worm gear
d. Spiral gear
45) In involute teeth, the pressure angle is often defined as the angle between the line of action and
the line of tangent to the pitch circle. It is also termed as:
a. Helix angle
b. Angle of recess
c. Angle of obliquity
d. Arc of action
