Question 1192897
The velocity of a sky diver t seconds after jumping is given by v(t) = 80(1 − e(-0.2t)). After how many seconds is the velocity 40 ft/s?
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v(t) = 80(1 − e(-0.2t)) = 40
(1 − e(-0.2t)) = 0.5
e(-0.2t) = 0.5
-0.2t = ln(0.5)
-t = 5*ln(0.5)
t = -5ln(0.5) =~ 3.466 seconds