Motion at changing speeds
Truck speeds
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Because of their heavy weight, the braking rate of trucks is lower
than that of passenger cars.
According to US standards for brakes, the
braking distance of a truck driving at 60 miles/hour
(96 km/hour) must be 335 feet (100 meters) at most. This
is much longer than the approximate 50-meter braking distance of passenger cars driving at the same speed.
It therefore seems reasonable to adopt a lower speed
limit for trucks than for passenger cars, which has been
done in several states in the US, as shown in the following table:
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Maximum speed for trucks (miles/hour)
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Maximum speed for cars (miles/hour)
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State
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55
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65
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Oregon
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60
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70
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Washington
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65
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75
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Montana
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55
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70
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California
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Investigate the effect of speed limits on trucks
Using the data above, construct descriptions
of the braking process of trucks and cars at different speeds.
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Do the lower speed limits for trucks make the braking
distances of cars and trucks driving at the maximum allowed speed about the
same?
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Do you recommend any changes in the current speed
limits for trucks in the states listed above?
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