A transmission shaft primarily carries torque and what?
A Heat flux only
B Fluid pressure
C Electrical current
D Bending moment
Answer: D. Bending moment. Power shafts commonly experience torsion along with bending from gears, belts or pulleys.
For a circular shaft, torsional shear stress is Tc divided by what?
A Area moment I only
B Length squared
C Polar moment J
D Elastic modulus
Answer: C. Polar moment J. The torsion formula is τ = Tc/J, with c the outer radius.
Angle of twist for a uniform shaft is what?
A JG / TL
B TL / JG
C TJG / L
D LJ / TG
Answer: B. TL / JG. Elastic twist is θ = TL/(JG) for a uniform circular shaft.
Polar moment for a solid circular shaft is what?
A πd⁴ / 32
B πd³ / 16
C πd² / 4
D πd⁴ / 64
Answer: A. πd⁴ / 32. For a solid circular section, J = πd⁴/32.
A shaft key primarily transmits what between hub and shaft?
A Axial heat
B Fluid pressure
C Radial clearance
D Torque
Answer: D. Torque. A key prevents relative rotation and transmits torque between a shaft and hub.
A sunk key is fitted partly into which parts?
A Bearing and frame
B Shaft and hub
C Gear teeth only
D Two couplings
Answer: B. Shaft and hub. A sunk key occupies keyways in both shaft and hub.
A Woodruff key has which general shape?
A Semicircular disk
B Tapered rod
C Rectangular plate
D Helical spring
Answer: A. Semicircular disk. A Woodruff key is a semicircular disk that can tilt slightly for alignment.
Splines transmit torque using what?
A Multiple shaft teeth
B One friction pad
C A single pin
D A belt groove
Answer: A. Multiple shaft teeth. Splines are multiple axial teeth that engage matching hub grooves.
A coupling connects which components?
A Shaft and bearing only
B Two shafts
C Gear and rack
D Spring and damper
Answer: B. Two shafts. Couplings join two shafts to transmit power.
A flexible coupling can accommodate what?
A Unlimited shaft offset
B Zero torque
C Permanent slip
D Small misalignment
Answer: D. Small misalignment. Flexible couplings tolerate limited angular, parallel or axial misalignment.
A flange coupling commonly uses what to join flanges?
A Bolts
B Worm gears
C Roller chains
D Cotter pins only
Answer: A. Bolts. Bolted flanges clamp the two coupling halves together.
Bolt preload helps resist joint separation by what?
A Reducing bolt length
B Clamping force
C Removing friction
D Increasing clearance
Answer: B. Clamping force. Preload creates compression in clamped parts and helps keep the joint closed.
Proof load is the maximum load before what?
A Elastic response
B Permanent set
C Surface polish
D Thermal expansion
Answer: B. Permanent set. Proof load is a specified tensile load that a fastener can sustain without permanent deformation.
Bolt tensile stress area represents what?
A Head bearing area
B Washer contact area
C Shank circumference
D Threaded tensile capacity
Answer: D. Threaded tensile capacity. The tensile-stress area accounts for reduced load-bearing area at the threads.
A bolted joint’s separation load depends partly on what?
A Tooth module
B Shaft key length
C Joint stiffness ratio
D Bearing speed only
Answer: C. Joint stiffness ratio. The stiffness split between bolt and clamped members determines how external load changes bolt force.
Power screw lead is axial travel per what?
A One revolution
B One tooth
C One thread root
D One degree
Answer: A. One revolution. Lead is the axial distance advanced in one full screw revolution.
A single-start screw lead equals what?
A Twice thread pitch
B Half thread pitch
C Thread pitch
D Screw diameter
Answer: C. Thread pitch. For a single-start screw, lead equals pitch.
A self-locking screw has friction angle greater than what?
A Helix angle twice
B Lead angle
C Pressure angle
D Shear angle
Answer: B. Lead angle. Self-locking occurs when the friction angle exceeds the helix or lead angle.
Screw efficiency is output work divided by what?
A Thread pitch
B Axial load
C Input work
D Screw length
Answer: C. Input work. Efficiency is useful output work divided by input work.
A fillet weld’s effective throat is approximately what?
A 0.707 times leg
B 1.414 times leg
C Half the leg
D Twice the leg
Answer: A. 0.707 times leg. For an equal-leg fillet weld, the throat dimension is about 0.707 times leg size.
Weld shear capacity depends on throat area and what?
A Gear ratio
B Shaft speed
C Spring index
D Allowable shear stress
Answer: D. Allowable shear stress. Weld resistance depends on effective throat area and allowable stress.
An eccentrically loaded weld group sees direct shear plus what?
A Secondary shear
B Only axial tension
C Pure compression
D No moment
Answer: A. Secondary shear. The eccentric moment creates a secondary shear distribution in addition to direct shear.
A riveted lap joint can fail by plate tearing or what?
A Gear tooth bending
B Spring buckling
C Rivet shear
D Bearing seizure
Answer: C. Rivet shear. Common riveted-joint failure modes include plate tearing, rivet shear and bearing failure.
Bearing stress in a pin joint uses load divided by what?
A Polar moment
B Shaft torsion
C Weld throat only
D Projected contact area
Answer: D. Projected contact area. Projected bearing area is pin diameter times the connected plate thickness.
A cotter joint primarily connects rods under what loading?
A Pure bending only
B Torsion only
C Axial tension or compression
D Alternating torque only
Answer: C. Axial tension or compression. Cotter joints connect co-axial rods carrying axial force.