SOLUTION: I have no idea on this question . I dont know what they want me to graph : a toy rocket is launched from a platform 20 feet above the ground with an initial velocity of 128 feet pe

Question 869917: I have no idea on this question . I dont know what they want me to graph : a toy rocket is launched from a platform 20 feet above the ground with an initial velocity of 128 feet per second. The equation for the height{in feet} of the rocket t seconds after being launched is h= -16t^2+128t+20
The graph of the height equation is?
a} Do i need vertex ,x interception and y interception?
b} from the question the equation should be 20=-16t^2+128t+20 ?
thank you
Answer by rothauserc(4718) (Show Source): You can put this solution on YOUR website!

This is a parabola with time (t) along the x axis and height (h) along the y axis. From the graph, the rocket looks like it achieves max height of 260 feet after 4 seconds.
Also, you can use calculus and take the first derivative and set it equal to 0 to determine the time t for the max height.
f' = -32t + 128
-32t + 128 = 0
32t = 128
t = 4
now we can determine the max height by subsituting for t in oringal equation
h = -16*4^2 +128*4 + 20 = 266 feet
the vertex of the parabola is (4, 266)

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