SOLUTION: A ball is thrown directly upward from the ground with an initial speed on 80 ft/s. How high will it go? When will it return to the ground?

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Question 329341: A ball is thrown directly upward from the ground with an initial speed on 80 ft/s. How high will it go? When will it return to the ground?
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Start with the function for the height (h)of an object thrown upward as a function of time (t).
h%28t%29+=+-16t%5E2%2Bv%5B0%5D%2At%2Bh%5B0%5D Where: h = height, t= time, v%5B0%5D = Initial upward velocity, and h%5B0%5D = initial height of the object.
h%28t%29+=+-16t%5E2%2B80%2At%2B0 First, find the time (t%5Bm%5D) at the maximum height.
t%5Bm%5D+=+-80%2F2%28-16%29 This is the time, in seconds, when the object reaches it maximum height.
t%5Bm%5D+=+5%2F2 now substitute this into the first function h%28t%29 to find the maximum height reached by the object.
h%285%2F2%29+=+-16%285%2F2%29%5E2%2B80%285%2F2%29 Evaluate.
h%285%2F2%29+=+100feet. This is the maximum height attained by the object.
Now you need to find the time (t) at which the (h) = 0, so...
0+=+-16t%5E2%2B80t Factor a t.
t%28-16t%2B80%29+=+0 so...
-16t%2B80+=+0
-16t+=+-80
t+=+5seconds. The object reaches the ground in 5 seconds.