Question 1128492
Use 4.9t^2 + v0t = s

a) A bolt falls off an airplane at an altitude of 500 m. Approximately how long does it take the bolt to reach the ground?
s = 4.9t^2 + v0t = 500
4.9t^2 = 500
t = sqrt(500/4.9) =~ 10.1 seconds
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b) A ball is thrown downward at a speed of 10 m/sec from an altitude of 500 m. Approximately how long does it take the ball to reach the ground?
Use s = -4.9t^2 + v0t --- It's -4.9t^2 as gravity acts downward
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At impact, s = 0
s = -4.9t^2 + 10t = 0
t = 0 --- ignore
t = 10/4.9 = 2.041 seconds at impact
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c) Approximately how far will an object fall in 8 sec, when thrown downward at an initial velocity of 10 m/sec from a plane?
s = -4.9t^2 - 10t --- both terms are downward --> both negative
Sub 8 for t, find s