CDL COMBINATION PRACTICE TEST NORTH CAROLINA

11. When coupling a tractor to a semi-trailer, after checking if the fifth-wheel is in proper position for coupling you should:
connect the air lines to the trailer.
secure the vehicle.
connect the electrical cord and check the air lines.
make sure the area around the vehicle is clear and the trailer wheels are chocked.
12. The service line:
carries air and is connected to relay valves which allow the trailer brakes to be applied more quickly.
carries power steering fluid to control the trailer brakes.
carries air to the parking brake to control the trailer brakes.
None of the above.
13. The crack-the-whip effect:
can cause a vehicle to tilt.
can turn the trailer over.
the ends of some vehicles to drag.
can cause problems for drivers coming toward you.
14. Most heavy vehicles require ________ change gears.
single clutching
double clutching
triple shifting
double shifting
15. Hydroplaning:
only occurs at extremely high speeds.
never occurs at speeds below 40 mph.
only happens when tire pressure is higher than normal.
can occur at speeds as low as 30 mph.
16. When backing a trailer, if you turn the wheel left:
the cab will go left and the trailer will go right.
the cab and the trailer will go left.
the cab will go right and the trailer will go left.
the cab and the trailer will go right.
17. Older trailers do not have spring brakes. If the air supply leaks away:
there will be no emergency brakes.
the ABS won't work properly.
the trailer will stop normally.
All of the above.
18. When you make a quick lane change, the crack-the-whip effect can turn the trailer over. The crack-the-whip effect is caused by:
worn tire tread.
the rear trailer of a triple.
strong wind.
rearward amplification.
19. Weight that is loaded so there is a high center of gravity:
causes greater chance of rollover.
reduces the chance that the load will shift to the side or fall off.
makes a vehicle easier to handle.
All of the above.
20. After starting the engine, oil pressure should rise to a normal level:
within 2 minutes.
within 6 minutes.
within 3 miles.
within seconds.
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