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college algebra help, gravity formula?
A rock is thrown upward with a velocity of 17 meters per second from the top of a 25 meter high liff, and it misses the cliff on the way back down. When will the rock be 8 meters from the water, below?
2 Answers
- az_lenderLv 78 years agoFavorite Answer
8 = 25 + 17t - (1/2)(9.8)t^2
49t^2 - 170t - 170 = 0
t = (170/98) plus or
minus (1/98)sqrt(170^2+196*170)
Only the "plus" makes physical sense
t = 1.735 + 1.545 = 3.38 seconds
- Anonymous8 years ago
The answer above, 3.38 seconds, fails the most elementary common-sense check.
How long does it take the stone to reach its maximum height?
And then to fall down to its starting point?
