SOLUTION: A man in a car takes 6 seconds to reach 60 miles per hour (from a standing start) and continies at that speed around a 2 mile circular test circuit.How long does he take to complet

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Question 226596: A man in a car takes 6 seconds to reach 60 miles per hour (from a standing start) and continies at that speed around a 2 mile circular test circuit.How long does he take to complete the 2 mile lap ?
Answer by Alan3354(69443) About Me  (Show Source):
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A man in a car takes 6 seconds to reach 60 miles per hour (from a standing start) and continies at that speed around a 2 mile circular test circuit.How long does he take to complete the 2 mile lap ?
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Assuming the acceleration is constant for the 6 seconds:
60 mph = 88 ft/sec
a = 88/6 ft/sec/sec for the 1st 6 seconds
s = at^2/2 = (44/3)*6^2/2 = 264 feet traveled in 6 seconds while accelerating.
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The rest of the 2 miles = 2*5280 - 264 feet = 10296 feet
10296/88 = 117 seconds.
117 + 6 = 123 seconds for the lap.