Question 199824
A red ball and a green ball are simultaneously tossed into the air.
 The red ball is given an initial velocity of 96 feet per second,
 and its height t seconds after it is tossed is 16t2 + 96t feet. 
The green ball is given an initial velocity of 80 feet per second,
 and its height t seconds after it is tossed is 16t2 + 80t feet.
:
a) Find a polynomial D(t) that represents the difference in
the heights of the two balls.
;
D(t) = red ball ht - green ball ht
D(t) = (-16t^2 + 96t) - (-16t^2 + 80t)
Remove brackets
D(t) = -16t^2 + 96t + 16t^2 - 80t
the t^2's cancel
D(t) = 96t - 80t
D(t) = 16t
:
:
b) How much higher is the red ball 2 seconds after the
balls are tossed?
:Substitute 2 for t in the above
D(t) = 16(2)
D(t) = 32 ft
:
:
c) In reality, when does the difference in the heights stop increasing?
:
A graph of this will make it easy to see
{{{ graph( 300, 200, -2, 8, -20, 140, -16x^2+96x, -16x^2+80x) }}}
In 5 sec when the green ball strikes the ground