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Automotive Servicing NC III study materials
Automotive Servicing NC III study resources

Automotive Servicing NC III practice questions

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Question 1Apply safety practices and environmental protection in automotive servicing

In an automotive workshop, which PPE is specifically required when using a compressed-air blow gun to dry brake components?

  1. Steel-toed boots only
  2. Cotton gloves without any eye protection
  3. Safety goggles and a dust mask or respirator Correct answer.
  4. A welding helmet with a dark filter

Explanation

Compressed air can launch brake dust, metal particles, and chemical residue toward the face, so eye protection plus respiratory protection is the minimum. Brake dust may contain harmful fibres and must not be inhaled. Footwear and gloves alone do not protect the eyes or lungs.

Question 2Apply safety practices and environmental protection in automotive servicing

Before working underneath a vehicle raised on a two-post hoist, what is the correct safety step?

  1. Ask a co-worker to hold the vehicle steady by hand
  2. Lower the vehicle until it rests on the hoist arms
  3. Leave the engine running so the brakes stay pressurised
  4. Place wheel chocks and confirm the lift locks are engaged Correct answer.

Explanation

A raised vehicle must be secured by the mechanical locks of the hoist and prevented from rolling with wheel chocks before anyone goes underneath. Hydraulic pressure alone can bleed off, so the mechanical lock is the real safeguard. Never rely on a person to stabilise a lifted vehicle.

Question 3Apply safety practices and environmental protection in automotive servicing

Which class of fire extinguisher is appropriate for a burning solvent pan in an automotive paint area?

  1. Class D dry powder extinguisher
  2. Class B foam or dry chemical extinguisher Correct answer.
  3. Wet chemical extinguisher for cooking oils
  4. Class A water extinguisher

Explanation

Solvents, thinners, and fuels are Class B flammable liquids, so a foam or dry chemical extinguisher rated for Class B is required. Water spreads burning solvent and can make the fire worse. Class D is for combustible metals and wet chemical is for kitchen fat fires.

Question 4Apply safety practices and environmental protection in automotive servicing

A technician must drain engine oil for disposal. Which practice complies with environmental protection requirements?

  1. Burn the used oil in an open drum behind the shop
  2. Mix used oil with used coolant in one drum to save space
  3. Pour the used oil into the workshop floor drain after dilution
  4. Store used oil in a labelled closed container for a licensed recycler Correct answer.

Explanation

Used oil is a regulated waste that must be kept segregated in clearly labelled, closed containers and handed to an authorised recycler or collector. Pouring it into drains contaminates waterways and is illegal in most jurisdictions. Mixing wastes or open burning increases pollution and disposal cost.

Question 5Apply safety practices and environmental protection in automotive servicing

When refilling a lead-acid battery in the workshop, which precaution protects both the technician and the environment?

  1. Wear eye protection and add distilled water in a ventilated area Correct answer.
  2. Seal the vent caps tightly before charging the battery
  3. Add acid concentrate to top up the electrolyte level
  4. Neutralise spilled electrolyte by flushing it into the drain

Explanation

Lead-acid batteries release hydrogen during charging and contain corrosive sulfuric acid, so eye protection and ventilation are essential. Only distilled water should be added because tap water minerals damage the plates. Spilled electrolyte must be absorbed and neutralised, never flushed to a drain.

Question 6Apply safety practices and environmental protection in automotive servicing

What is the primary reason for connecting the ground clamp last and as close as possible to the weld joint when arc welding on a vehicle?

  1. It prevents the welding helmet from fogging
  2. It reduces the chance of current arcing through bearings and electronic modules Correct answer.
  3. It improves the appearance of the weld bead
  4. It allows a higher welding current to be used

Explanation

Welding current follows the path of least resistance back to the ground clamp. Placing the clamp near the joint keeps current out of bearings, fuel lines, and electronic control units that could be damaged or ignited. Weld appearance and helmet fogging are unrelated to clamp placement.

Question 7Apply safety practices and environmental protection in automotive servicing

Which statement correctly describes the purpose of a safety data sheet (SDS) for a brake cleaner used in the shop?

  1. It certifies that the product is safe for unrestricted use
  2. It gives the retail price and warranty of the product
  3. It replaces the need for labelling the secondary spray bottle
  4. It lists hazards, handling, PPE, and first-aid measures for the chemical Correct answer.

Explanation

An SDS communicates the hazards of a chemical and the controls needed: PPE, ventilation, storage, spill response, and first aid. It does not declare a product harmless, and it never replaces the requirement to label containers decanted in the shop. Commercial details are outside its scope.

Question 8Apply safety practices and environmental protection in automotive servicing

A vehicle is being run inside the workshop for diagnostics. Which control best prevents carbon monoxide exposure?

  1. Connecting an exhaust extraction hose to the tailpipe Correct answer.
  2. Placing a fan behind the vehicle
  3. Running the engine only at idle speed
  4. Opening one small window near the bay

Explanation

Carbon monoxide is odourless and can accumulate fatally even at idle, so the exhaust must be ducted directly outdoors with an extraction hose. A fan or open window dilutes but does not reliably remove the gas. Idle speed still produces dangerous CO concentrations over time.

Question 9Apply safety practices and environmental protection in automotive servicing

What is the correct action when a small amount of coolant splashes onto the workshop floor?

  1. Wash it into the drain with plenty of water
  2. Leave it to evaporate naturally
  3. Absorb it with inert material, clean the area, and dispose of the absorbent as directed Correct answer.
  4. Cover it with cardboard and continue working

Explanation

Coolant contains ethylene glycol or propylene glycol and must be contained before it reaches drains or animals. Absorbing with inert material and disposing of it through the proper waste route is the compliant response. Spills also create a slip hazard that must be removed promptly.

Question 10Apply safety practices and environmental protection in automotive servicing

Which practice reduces the risk of hand injury when using a bench grinder to sharpen a chisel?

  1. Adjust the tool rest close to the wheel and use a face shield Correct answer.
  2. Remove the spark guard to see the work better
  3. Wear loose-fitting gloves and hold the tool by hand
  4. Grind on the side of the wheel with light pressure

Explanation

A tool rest set within about 3 mm of the wheel prevents the workpiece from being drawn into the gap, and a face shield protects against flying fragments. Loose gloves and side-grinding are common causes of entanglement and wheel burst. The spark guard must remain in place.

Question 11Apply safety practices and environmental protection in automotive servicing

A technician notices that the insulation on an electric impact wrench's power cord is cut, exposing the conductor. What is the correct response?

  1. Plug it into a circuit breaker outlet to make it safe
  2. Wear rubber gloves and keep using the tool until the shift ends
  3. Wrap the cut with ordinary tape and continue using the tool
  4. Tag the tool out of service and report it for repair or replacement Correct answer.

Explanation

Damaged insulation defeats the tool's double insulation or earthing and creates a shock hazard, so the tool must be withdrawn from service and tagged. Repairs must be done by a competent person. Rubber gloves and circuit breakers do not restore the integrity of the cord.

Question 12Apply safety practices and environmental protection in automotive servicing

Why must a refrigerant recovery machine be used instead of venting an air-conditioning system to the atmosphere during servicing?

  1. Refrigerant damages the ozone layer or contributes to global warming Correct answer.
  2. Venting causes the system oil to freeze in the lines
  3. Recovered refrigerant can be resold to the customer for profit
  4. The compressor will not run unless the machine is connected

Explanation

Refrigerants such as R-134a and R-1234yf are greenhouse gases, and older CFC or HCFC refrigerants also deplete stratospheric ozone. Environmental regulations therefore require recovery and recycling rather than venting. Profit and compressor operation are not the governing reasons.

Question 13Apply safety practices and environmental protection in automotive servicing

Which condition indicates that a portable fire extinguisher in the workshop is due for recharge?

  1. The extinguisher was inspected last month
  2. The pressure gauge reads in the red or the seal is broken Correct answer.
  3. The safety pin is in place with a tamper seal
  4. The gauge needle sits in the green zone

Explanation

A needle in the red zone means the extinguisher lacks the pressure to discharge effectively, and a broken tamper seal suggests it may have been used or tampered with. Either condition requires recharge or replacement before it is relied upon. A green gauge and intact seal indicate a serviceable unit.

Question 14Apply safety practices and environmental protection in automotive servicing

What is the safest way to store oxy-acetylene cylinders in the workshop?

  1. Keep them next to the paint mixing area for convenience
  2. Lay them horizontally under a bench to save space
  3. Chain the cylinders together with the regulators left attached and pressurised
  4. Store them upright, secured, with caps fitted and away from ignition sources Correct answer.

Explanation

Compressed gas cylinders must stand upright and be secured against falling, with valve protection caps fitted when not in use, and kept away from heat and ignition sources. Acetylene cylinders in particular must never be laid down because liquid acetone can enter the valve. Regulators should be removed or isolated when cylinders are stored.

Question 15Apply safety practices and environmental protection in automotive servicing

During a brake job, a technician finds the friction material may contain asbestos. Which control is most appropriate?

  1. Dry-brush the dust away and sweep the floor afterwards
  2. Wipe the components with a dry rag and dispose of the rag in general waste
  3. Use a wet method or enclosed vacuum with HEPA filtration and wear respiratory protection Correct answer.
  4. Blow the dust off with compressed air from a distance

Explanation

Asbestos fibres become airborne when dry dust is disturbed and can cause serious lung disease, so wet methods or HEPA-filtered extraction are required. Dry brushing, compressed air, and dry wiping all aerosolise fibres. Waste containing asbestos must go through the hazardous waste route, not general refuse.

Question 16Apply safety practices and environmental protection in automotive servicing

A workshop stores new oil, used oil, and solvent in similar unmarked drums. Which action best prevents a hazardous waste violation?

  1. Store all drums on bare concrete near the floor drain
  2. Fill each drum completely to the top to avoid headspace
  3. Rely on staff memory to know which drum holds which liquid
  4. Label each drum with its contents and hazard class and keep them in a bunded area Correct answer.

Explanation

Clear labelling and segregation plus secondary containment (bunding) are the core requirements for storing liquids that could pollute. Unlabelled drums make accidental mixing and illegal disposal likely. Storing near a drain or overfilling increases spill risk rather than reducing it.

Question 17Apply safety practices and environmental protection in automotive servicing

Which is the correct first action when a co-worker's clothing catches fire in the workshop?

  1. Spray the person with the nearest CO2 extinguisher
  2. Fan the flames with a piece of cardboard
  3. Stop, drop, and roll the person and smother the flames with a fire blanket Correct answer.
  4. Run to the office to call the supervisor before acting

Explanation

Smothering burning clothing with a fire blanket and stopping the person from running cuts off oxygen and limits flame spread. Running or fanning feeds the fire with air. A CO2 extinguisher can cause cold burns and does not smother clothing well. Delaying action to make a call lets the injury worsen.

Question 18Apply safety practices and environmental protection in automotive servicing

Why should a vehicle's airbag system be deactivated according to the manufacturer's procedure before steering wheel or dashboard work?

  1. To make the steering wheel easier to turn
  2. To improve fuel economy during the repair
  3. To reset the clock spring automatically
  4. To prevent the airbag from deploying unexpectedly and injuring the technician Correct answer.

Explanation

An undeployed airbag contains a pyrotechnic charge that can fire if a sensor or circuit is disturbed, causing serious injury at close range. The manufacturer's procedure includes disconnecting power and waiting for the capacitor to discharge. Handling convenience, fuel economy, and clock spring resetting are not safety reasons.

Question 19Apply safety practices and environmental protection in automotive servicing

A technician must dispose of a used oil filter and a nickel-cadmium battery pack. Which statement reflects correct waste segregation?

  1. The battery can be stored with scrap steel for the metal recycler
  2. The oil filter is drained and recycled as metal, and the NiCd battery is sent as hazardous waste Correct answer.
  3. Both can go into general waste because they are small items
  4. Both should be placed in the same bin for incineration

Explanation

Used oil filters are drained and then recycled as scrap metal, while nickel-cadmium batteries are hazardous waste containing heavy metals that require a dedicated collection route. Mixing either with general waste or scrap steel defeats recycling and can cause fires or contamination. Small size does not exempt hazardous items.

Question 20Apply safety practices and environmental protection in automotive servicing

What is the purpose of a lockout/tagout procedure when servicing the electrical system of a hybrid vehicle?

  1. To isolate the high-voltage source and prevent accidental re-energising Correct answer.
  2. To prevent the customer from seeing the repair invoice
  3. To record the technician's working hours on the vehicle
  4. To lock the vehicle doors during the repair

Explanation

Lockout/tagout physically isolates the energy source and attaches a warning tag so that no one can restore power while work is in progress. On hybrid vehicles this is critical because the high-voltage system can cause fatal shock. Timekeeping, door locking, and billing are unrelated to the procedure.

Question 21Use and maintain hand tools, power tools, and shop equipment

When using a torque wrench to tighten cylinder head bolts, what does the click-type mechanism signal to the technician?

  1. The preset torque value has been reached Correct answer.
  2. The wrench needs to be recalibrated immediately
  3. The socket has reached the correct angle of rotation
  4. The fastener threads have started to strip

Explanation

A click-type torque wrench releases a spring-loaded internal mechanism that produces an audible click and a slight feel change when the set torque is achieved. The technician must stop applying force at that moment to avoid over-torquing the fastener.

Question 22Use and maintain hand tools, power tools, and shop equipment

A technician must loosen a tightly seized wheel lug nut. Which combination of hand tools is most appropriate and safe?

  1. A short 1/4-inch ratchet with a deep socket
  2. An adjustable wrench applied to the nut flats
  3. A breaker bar with a six-point socket of the correct size Correct answer.
  4. A torque wrench used in the loosen direction

Explanation

A breaker bar is designed to deliver high leverage without an internal ratchet mechanism that can fail under heavy load. A six-point socket of the exact size grips the nut flats fully and reduces the risk of rounding.

Question 23Use and maintain hand tools, power tools, and shop equipment

Before connecting an impact wrench to the shop air line, what is the primary purpose of the in-line lubricator and filter unit (FRL)?

  1. To increase air pressure above line pressure
  2. To cool the compressed air before it enters the tool
  3. To regulate the direction of tool rotation
  4. To remove moisture and debris and add oil mist to the air Correct answer.

Explanation

An FRL unit combines a filter that traps water and particulate, a regulator that sets pressure, and a lubricator that injects oil mist. Clean, lubricated air extends the life of pneumatic impact tools and maintains consistent power.

Question 24Use and maintain hand tools, power tools, and shop equipment

A hydraulic floor jack is used to raise a vehicle for underbody inspection. Which practice best satisfies shop safety requirements?

  1. Support the vehicle on the jack alone while a coworker watches
  2. Place a wooden block on the jack saddle and rely on the jack's hydraulic hold
  3. Keep the jack handle locked in the raised position and work quickly beneath the vehicle
  4. Lower the vehicle onto jack stands placed at the manufacturer's lift points before going underneath Correct answer.

Explanation

A hydraulic jack is a lifting device only; hydraulic seals can fail without warning. Jack stands placed at the specified lift points provide stable mechanical support before any part of the body goes under the vehicle.

Question 25Use and maintain hand tools, power tools, and shop equipment

A bench grinder wheel must be inspected before use. Which condition requires the wheel to be removed from service?

  1. The wheel runs with a light vibration at start-up
  2. The wheel has a visible crack or chip on its face Correct answer.
  3. The wheel shows a slight uniform grey colour
  4. The wheel has been dressed within the last week

Explanation

Cracks and chips in an abrasive wheel can cause it to shatter at operating speed, throwing fragments at high velocity. Any wheel with visible damage must be discarded regardless of remaining thickness.

Question 26Use and maintain hand tools, power tools, and shop equipment

When using a digital multimeter to check for voltage at a fuel injector connector on a live circuit, which meter setting is correct?

  1. DC volts with the probes across the connector terminals while cranking Correct answer.
  2. Continuity with the ignition off
  3. Resistance (ohms) with the circuit powered
  4. Current (amps) with the probes in parallel to the load

Explanation

Voltage is measured in parallel with the circuit while it is powered, using the DC volts range appropriate to the expected signal. Probing the injector connector while cranking captures the pulsed command voltage.

Question 27Use and maintain hand tools, power tools, and shop equipment

A technician is choosing a socket for a rusted 12 mm hex bolt head. Which socket feature best reduces the chance of rounding the fastener?

  1. A 1/4-inch drive socket with an extension
  2. A 12-point socket with a chrome finish
  3. A universal joint socket with a shallow depth
  4. A 6-point socket with a tight-fitting flank-drive profile Correct answer.

Explanation

Six-point sockets contact the fastener on the flats rather than the corners, and flank-drive geometry distributes load away from the corners. This greatly reduces the risk of rounding a corroded or tight bolt head.

Question 28Use and maintain hand tools, power tools, and shop equipment

After using a micrometer to measure a crankshaft journal, what is the correct maintenance step before storing the tool?

  1. Close the spindle firmly against the anvil to protect the thread
  2. Store it with the thimble locked at zero
  3. Apply a light coat of penetrating oil to the measuring faces
  4. Leave the spindle open slightly and wipe the measuring faces with a clean cloth Correct answer.

Explanation

Measuring faces should be cleaned after use and the spindle left slightly open to relieve thread pressure and prevent corrosion between the faces. This preserves accuracy and protects the precision thread.

Question 29Use and maintain hand tools, power tools, and shop equipment

A hydraulic press is used to remove a wheel bearing from a knuckle. Which practice protects both the operator and the press?

  1. Stand directly in front of the ram to watch the bearing move
  2. Apply full pressure quickly to break the bearing free
  3. Use a socket that is smaller than the bearing outer race to concentrate force
  4. Stand to the side of the press and use a correctly sized driver or adapter on the bearing race Correct answer.

Explanation

Standing to the side keeps the operator out of the line of fire if a component shatters, and a correctly sized driver applies force to the intended race. Sudden release of stored energy is the main hazard in press work.

Question 30Use and maintain hand tools, power tools, and shop equipment

Which tool is specifically designed to measure the inside diameter of a cylinder bore accurately?

  1. A vernier caliper with inside jaws
  2. A feeler gauge set
  3. A telescoping gauge used with an outside micrometer Correct answer.
  4. An outside micrometer

Explanation

A telescoping gauge is set to the bore diameter and then measured with an outside micrometer to obtain a precise reading. This transfer method gives the accuracy needed for cylinder wear and taper checks.

Question 31Use and maintain hand tools, power tools, and shop equipment

A technician uses an angle grinder with a cutting disc to trim a metal bracket. Which PPE combination is required for this task?

  1. Dust mask and cotton work gloves only
  2. Face shield, safety glasses, hearing protection, and gloves Correct answer.
  3. Safety glasses only
  4. Welding helmet and leather apron only

Explanation

An angle grinder produces sparks, high-velocity fragments, noise, and abrasive dust. Layered eye protection with a face shield, plus hearing protection and gloves, addresses all these hazards.

Question 32Use and maintain hand tools, power tools, and shop equipment

A pneumatic impact wrench loses power and runs sluggishly. Which maintenance check is most likely to identify the cause?

  1. Replace the impact wrench anvil
  2. Increase the torque setting on the tool
  3. Check the air line for kinks, a clogged filter, or an undersized quick coupler Correct answer.
  4. Change the socket to a longer extension

Explanation

Loss of pneumatic power usually comes from restricted air flow or pressure drop. Kinked hoses, a saturated filter element, or restrictive quick couplers starve the tool of the volume it needs.

Question 33Use and maintain hand tools, power tools, and shop equipment

Which practice is correct when using a feeler gauge to measure valve clearance on an overhead camshaft engine?

  1. Measure the gap with the engine at normal operating temperature regardless of specification
  2. Use the gauge to lever the rocker arm for access
  3. Force the thickest blade that will fit into the gap
  4. Slide blades of increasing thickness until one produces a light drag in the gap Correct answer.

Explanation

The correct clearance is the blade that slides through the gap with a light, even drag. Forcing a blade or using it as a lever damages the gauge and gives a false reading.

Question 34Use and maintain hand tools, power tools, and shop equipment

A technician needs to remove a small snap ring from a gearbox shaft. Which tool is designed for this task?

  1. A hammer and punch
  2. A flat-blade screwdriver
  3. A snap ring (circlip) pliers with the correct jaw type Correct answer.
  4. A pair of locking pliers

Explanation

Snap ring pliers engage the ring's eyelets and compress or expand it evenly for safe removal. Using the correct jaw type (internal or external) prevents the ring from springing free and causing injury.

Question 35Use and maintain hand tools, power tools, and shop equipment

When using a bench vise to hold a component for filing, which practice protects the workpiece and the vise?

  1. Leave the vise slightly loose so the part can rotate freely
  2. Tighten the jaws with a pipe extension for maximum grip
  3. Hold the workpiece by only one corner in the jaws
  4. Use soft jaws or jaw caps and tighten firmly but without overloading the screw Correct answer.

Explanation

Soft jaws or caps distribute clamping force and prevent marring of finished surfaces. Firm but moderate tightening avoids overstressing the vise screw and slide.

Question 36Use and maintain hand tools, power tools, and shop equipment

A technician is about to use an oxy-acetylene torch to heat a seized exhaust bolt. Which safety action is essential before lighting the torch?

  1. Point the torch tip toward the vehicle interior to check flame shape
  2. Test for leaks by holding a lit match near the regulator
  3. Open the acetylene cylinder valve fully and leave the key in place
  4. Check for leaks with a soap solution and confirm a flashback arrestor is fitted Correct answer.

Explanation

Leak testing with soap solution is the safe method for finding gas leaks, and flashback arrestors on the regulators prevent flame from travelling back into the cylinders. Acetylene cylinder valves should be opened only about one turn.

Question 37Use and maintain hand tools, power tools, and shop equipment

Which tool is appropriate for checking the runout of a brake disc mounted on the vehicle?

  1. A torque wrench
  2. A dial indicator with a magnetic base Correct answer.
  3. A compression gauge
  4. A depth micrometer

Explanation

A dial indicator with a magnetic base is mounted to a fixed point and its stylus rests on the disc surface to read lateral runout as the disc rotates. This reveals warping or uneven mounting.

Question 38Use and maintain hand tools, power tools, and shop equipment

A hydraulic engine crane is used to lift an engine from a bay. Which step best prevents the load from shifting during the lift?

  1. Balance the load with a leveling device and keep the boom low and the load close to the base Correct answer.
  2. Extend the boom fully to reach the engine without moving the crane
  3. Attach the sling to a single convenient bolt on the cylinder head
  4. Lift the engine quickly to clear the fenders before it can swing

Explanation

Keeping the load close to the crane base and the boom low reduces the overturning moment on the crane. A leveling device balances the engine so it does not swing or shift during the lift.

Question 39Use and maintain hand tools, power tools, and shop equipment

Why must a torque wrench be stored at its lowest setting after use?

  1. To make the wrench easier to find in the toolbox
  2. To prevent the socket from rusting
  3. To relieve spring tension and preserve calibration accuracy Correct answer.
  4. To keep the scale from fading

Explanation

Leaving a click-type torque wrench at a high setting keeps the internal spring compressed, causing it to take a set and drift from calibration. Backing off to the lowest setting relieves that tension between uses.

Question 40Use and maintain hand tools, power tools, and shop equipment

A technician is drilling a hole in a steel bracket with a bench drill press. Which setup best protects the operator and produces an accurate hole?

  1. Clamp the bracket to the table, centre-punch the hole, and use the correct speed and feed Correct answer.
  2. Set the drill to maximum speed for faster cutting
  3. Hold the bracket by hand and feed the drill slowly
  4. Wear gloves and hold the bracket against the column

Explanation

Clamping the workpiece prevents it from spinning or being snatched by the drill, and a centre punch guides the bit to the marked location. Correct speed and feed for the material produce a clean, accurate hole.

Question 41Perform mensuration and calculation

A cylinder bore measures 85.00 mm and the piston skirt measures 84.94 mm. What is the piston-to-bore clearance?

  1. 0.94 mm
  2. 0.12 mm
  3. 1.06 mm
  4. 0.06 mm Correct answer.

Explanation

Clearance is the bore diameter minus the piston diameter: 85.00 - 84.94 = 0.06 mm. Clearance is always a difference between two measured diameters, so the result keeps the same unit as the inputs.

Question 42Perform mensuration and calculation

An engine specification states valve clearance of 0.010 inch. What is this value in millimeters, to two decimal places?

  1. 0.39 mm
  2. 2.54 mm
  3. 0.04 mm
  4. 0.25 mm Correct answer.

Explanation

One inch equals 25.4 mm, so 0.010 inch x 25.4 = 0.254 mm, which rounds to 0.25 mm. Converting inches to millimeters always multiplies by 25.4.

Question 43Perform mensuration and calculation

A torque wrench is set to 90 N·m. Using the conversion 1 kgf·m = 9.81 N·m, what is the nearest equivalent in kgf·m?

  1. 0.11 kgf·m
  2. 883 kgf·m
  3. 9.2 kgf·m Correct answer.
  4. 90 kgf·m

Explanation

Divide the newton-meter value by 9.81: 90 / 9.81 = 9.17, which rounds to 9.2 kgf·m. Because 1 kgf·m is nearly ten times larger than 1 N·m, the kgf·m figure must be much smaller than 90.

Question 44Perform mensuration and calculation

The bore and stroke of a four-cylinder engine are both 86.0 mm. Using pi = 3.1416, what is the total engine displacement in cubic centimeters, rounded to the nearest whole number?

  1. 1998 cc Correct answer.
  2. 500 cc
  3. 2497 cc
  4. 7992 cc

Explanation

Swept volume per cylinder equals pi/4 x bore squared x stroke. With bore and stroke of 8.60 cm, that is 0.7854 x 73.96 x 8.60 = 499.5 cc, and four cylinders give about 1998 cc.

Question 45Perform mensuration and calculation

A micrometer thimble has 50 divisions and one full thimble revolution advances the spindle 0.50 mm. What does one thimble division represent?

  1. 0.50 mm
  2. 0.05 mm
  3. 0.01 mm Correct answer.
  4. 0.10 mm

Explanation

Divide the spindle advance per revolution by the number of thimble divisions: 0.50 mm / 50 = 0.01 mm. Each division therefore represents one hundredth of a millimeter.

Question 46Perform mensuration and calculation

A dial indicator is mounted with its stem perpendicular to a rotating shaft. The indicator reads 0.00 mm at the top and 0.12 mm at the bottom. What does this indicate about the shaft?

  1. The shaft runout is 0.24 mm
  2. The shaft is correctly aligned
  3. The shaft is bent by 0.12 mm
  4. The shaft is offset by 0.06 mm from the indicator axis Correct answer.

Explanation

A total indicator reading of 0.12 mm across opposite points represents twice the offset, so the centerline is displaced by 0.06 mm. This is the standard half-difference rule for centering a shaft.

Question 47Perform mensuration and calculation

A fastener must be tightened to 45 N·m, but the only wrench available is calibrated in lbf·ft. Using 1 N·m = 0.7376 lbf·ft, what setting is nearest?

  1. 33 lbf·ft Correct answer.
  2. 45 lbf·ft
  3. 61 lbf·ft
  4. 10 lbf·ft

Explanation

Multiply by the conversion factor: 45 x 0.7376 = 33.2, so 33 lbf·ft is the nearest setting. The lbf·ft value is always smaller than the N·m value because one lbf·ft equals about 1.356 N·m.

Question 48Perform mensuration and calculation

A technician records a cylinder bore of 3.386 inches and needs the value in millimeters for a specification table. Using 1 inch = 25.4 mm, what should be entered, to one decimal place?

  1. 13.3 mm
  2. 86.0 mm Correct answer.
  3. 86.4 mm
  4. 8.6 mm

Explanation

Multiplying 3.386 inches by 25.4 gives 86.0 mm to one decimal place. Recording the converted value with the correct number of significant figures keeps the specification table consistent with metric tooling.

Question 49Perform mensuration and calculation

A feeler gauge set is used to check valve clearance, and the specification is 0.20 mm. Which combination of blades gives exactly 0.20 mm?

  1. 0.10 mm plus 0.10 mm Correct answer.
  2. 0.05 mm plus 0.10 mm
  3. 0.15 mm plus 0.10 mm
  4. 0.20 mm plus 0.05 mm

Explanation

Stacked feeler blades add their thicknesses, so two 0.10 mm blades give exactly 0.20 mm. Any combination must sum to the specified clearance, not exceed or fall short of it.

Question 50Perform mensuration and calculation

A four-cylinder engine has a bore of 90.0 mm and a stroke of 100.0 mm. A replacement piston increases the swept volume per cylinder by 5 percent. Using pi = 3.1416, what is the new total displacement, rounded to the nearest cubic centimeter?

  1. 636 cc
  2. 2545 cc
  3. 3182 cc
  4. 2670 cc Correct answer.

Explanation

Original swept volume per cylinder is 0.7854 x 81.00 x 10.00 = 636 cc, so four cylinders give 2545 cc. Increasing by 5 percent gives 2545 x 1.05 = 2672, which rounds to about 2670 cc.