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maximum height

by apoorva.srivastva » Wed Jun 24, 2009 9:12 am
An object thrown directly upward is at a height of h feet after t seconds, where h = -16 (t - 3)^2 + 150. At what height, in feet, is the object 2 seconds after it reaches its maximum height?

A. 6
B. 86
C. 134
D 150
E. 214
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by Robinmrtha » Wed Jun 24, 2009 9:19 am
the maximum height the object can reach is when t=3...
i.e. h=150
So, we need to find the height when t=3+2= 5
Put the value of t=5 in the equation
We get 86
Answer is B
Whats the OA?
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by tohellandback » Wed Jun 24, 2009 9:20 am
https://www.beatthegmat.com/an-object-th ... 38681.html
The powers of two are bloody impolite!!
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by SanjeevK » Wed Jun 24, 2009 9:22 am
Assuming no complicated physics is applied :)
IMO B:

Since the expression is: h = -16 (t - 3)^2 + 150, the maximum height will be 150 ft. This will happen when t = 3 secs.
Hence 2 sec after the maximu height is reached is 2+3 = 5 sec

Put t = 5 in the expression
h = -16(2)^2 + 150 = 86.

Hope this helps
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by apoorva.srivastva » Wed Jun 24, 2009 10:20 am
OA is 86
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