Question 561682: This is a real world math problem:
Is it possible to accelerate from 45 mph to 71 mph in 20 seconds and then safely return to 50 mph in .8 miles? The car is a 2011 Kia Forte Koup EX 2dr FWD. Engine: 2.0L 1-4 Engine. Power: 156@6,200 rpm. Automatic transmission. 0-60 in 7.6 seconds. According to a test drive I saw on you tube it went from 45 to 71 in 20 seconds.
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! Is it possible to accelerate from 45 mph to 71 mph in 20 seconds and then safely return to 50 mph in .8 miles? The car is a 2011 Kia Forte Koup EX 2dr FWD. Engine: 2.0L 1-4 Engine. Power: 156@6,200 rpm. Automatic transmission. 0-60 in 7.6 seconds. According to a test drive I saw on you tube it went from 45 to 71 in 20 seconds.
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0 to 60 mi/hr = 0 to 88 ft/sec
88/7.6 =~ 11.6 ft/sec/sec acceleration =~ 0.36 g
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71 - 45 = 26 mi/hr = 38 ft/sec change in speed
38/20 = 1.9 ft/sec/sec =~ 0.06 g
Not a lot of acceleration, but "top end" might be an issue.
If the acceleration is constant, which is seldom the case, the distance covered during the acceleration from 45 to 71 in 20 seconds = 1701 feet = 0.32 miles
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Slowing from 71 to 50 mi/hr in 0.8, or in the remaining 0.48 miles, is easy.
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