Question 571968
A ball is thrown vertically upward with a speed of 100 mph.
How long does it take the ball to reach its maximum height? in seconds.
:
They want this in meters, convert 100 mph to meters per second
{{{(100*5280)/3600}}} * .3048 = 44.7 m/sec
:
Let t = time in sec
Let h(t) = height at t time
;
h(t) = -4.9t^2 + 44.7t 
;
Max occurs at the axis of symmetry: x = -b/(2a)
t = {{{(-44.7)/(2*-4.9)}}}
t = 4.56 seconds to reach max height
:
"What is the ball's maximum height? in meters"
Replace 4.56 sec in the original equation
h = -4.9(4.56^2) + 44.7(4.56)
h = -101.9 + 208.8
h = 101.9 meter max height