Math B June 2007 non-multiple choice #32

[johnyoun]

how would you solve this problem
The path of a rocket fired during a fireworks display is given by the equation s(t)=64t-16t^2
where t is the time, in seconds, and s is the height,in feet. what is the maximum height, in feet, the rocket will reach? In how many seconds will the rocket hit the ground?
up there the ^2 means t to the second power.

please respond

 

[arthur ohlsten]

If you were studying calculus you would take the derivative with respect to t , and set it equal to zero. I assume you aren't studying calculus.
If we sketch the curve:
s=64t-16t^2 we see it is symetric.
s=0 at t=0 and at ?
0=t[64-16t]
t=0 or t=4

it reaches a maximum at t=2,which you can calculate, and reaches the ground at t=4
Arthur,