V/-8 = 4v
V= -32v
V+32v=0
33v=0
V=0
Check the picture below.
now, the "x" is a constant, the rocket is going up, so "y" is changing and so is the angle, but "x" is always just 15 feet from the observer. That matters because the derivative of a constant is zero.
now, those are the values when the rocket is 30 feet up above.

Answer:
All of above
Step-by-step explanation:
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