Question 1118705
A video tracking device recorded the height h, in metres, of a baseball after it was hit into the air. The data collected can be modelled by the quadratic relation h=-3(t-3)^2+18, where t is the time in seconds after the ball was hit.

a) What was the maximum height reached by the baseball?
b) When did the baseball reach its maximum height?
c) At what time(s) was the baseball at the height of 10m?
d) Approximately when did the baseball hit the ground?



Thank you
<pre>{{{matrix(1,3, h, "=", - 3(t - 3)^2 + 18)}}}
Vertex can be read from the equation as it's in vertex form. 
<b><u>Vertex: (3, 18)</b></u>
a) is answered as the y-coordinate of the vertex is 18 m.
b) is also answered as the x-coordinate of the vertex is 3 seconds.
c) The answers to this is about 1.4 seconds and again at 4.6 seconds.
d) Set the equation equal to 0, and solve to get t = 0.55 and t = 5.449489743, or t = 5.45 seconds, approximately
   but the larger t-value, or 5.45 seconds is the time it takes to hit the ground.
IGNORE all other USUAL WRONG answers!!