The acceleration rate
2008-12-03 10:19 pm
Suppose a particular jet needs to attain a speed of 220 mph to take off. If it can accelerate from 0 to 220 mph in 30 seconds, how long must the runway be? Assume constant acceleration. Note: 1 mph = 22/15 ft/sec.
回答 (1)
2008-12-04 12:44 am
✔ 最佳答案
s = at^2/2.............(1) since u = 0.v = at..................(2)
From (2) t = v/a. Sub into (1)
s = a[(v/a]^2/2.
2as = v^2
Now v = 220, a = 220/30 x 2 x 60.
so 2 x 220/30 x 2 x 60 x s = 220 x 220
8s = 220
s = 27.5 miles.
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