MASSACHUSETTS CDL AIR BRAKES PRACTICE TEST
21.
To make the brakes work, air brakes use:
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compressed air.
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hydraulic air.
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nitrogen.
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carbon monoxide.
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22.
In a vehicle with a dual air brake system:
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both systems typically operate the regular brakes on the rear axle.
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each system has its own air tanks.
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one system supplies air to the trailer.
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All of the above.
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23.
Emergency brakes are:
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not required on doubles.
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not required on buses.
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required on all vehicles.
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not required on commercial vehicles with air brakes.
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24.
What factors can cause brakes to fade?
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Excessive heat and brakes out of adjustment.
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Slippery surfaces and shaded areas.
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Dirt roads and in unpaved yards.
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Gravel and tar.
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25.
The air brake lag distance at 55 mph on dry pavement adds about:
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60 feet.
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16 feet.
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75 feet.
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32 feet.
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