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If an object is thrown vertically upward with an initial velocity of v, from an...
If an object is thrown vertically upward with an initial velocity of v, from an original position of s, the height h at any time t is given by: h = -16t^2 + vt + s (where h and s are in ft, t is in seconds and v is in ft/sec.)
If a rock is thrown upward from a height of 100 ft, with an initial velocity of 32 ft/sec, sholve for the itme that it takes for it to hit the ground (when h = 0).
Round your answer to 2 decimals.
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High School Teacher
`h = -16t^2 + vt + s`
s = original position = 100ft
v = 32 ft/sec
h = 0 when it hits ground
Solve for t.
`0 = -16t^2 + 32t + 100`
`0 = (-32+-sqrt(32^2 - 4(-16)(100)))/(2(-16))`
`0 = (-32+-sqrt(7424))/-32`
`0 = -1.6925and 3.6925`
Since time is not negative, -1.6925 is an extraneous solution, therefore it takes 3.69 seconds for the object to hit the ground.
Posted by baxthum8 on September 20, 2013 at 11:33 PM (Answer #1)
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