Asked by jean
a parachutist falling at the rate of 15 ft./sec. drops a stone. if he was 904 ft. above the ground when the stone was dropped, how long would it take the stone to reach the ground?
Answers
Answered by
Reiny
assuming a = -32
and seeing that the initial velocity was -15 from a height of 904, I know
s = -16r^2 - 15t + 904
we want s = 0
16t^2 + 15t - 904 = 0
won't waste time trying to factor it ...
t = (-15 ± √58081)/32
= (-15 ± 241)/32 ----- ahh, it does factor
= 226/32 or some silly negative
= 113/16 seconds or appr 7.1 seconds
btw, it would have been factored as
(16t - 113)(t + 8) = 0
and seeing that the initial velocity was -15 from a height of 904, I know
s = -16r^2 - 15t + 904
we want s = 0
16t^2 + 15t - 904 = 0
won't waste time trying to factor it ...
t = (-15 ± √58081)/32
= (-15 ± 241)/32 ----- ahh, it does factor
= 226/32 or some silly negative
= 113/16 seconds or appr 7.1 seconds
btw, it would have been factored as
(16t - 113)(t + 8) = 0
Answered by
jean
Thank you. You’re so helpful.
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.