Question
An object is projected directly upward from the ground. After t seconds it’s distance in feet above the ground is s=144t-16t^2
How long does it take the object to reach its maximum height?
What is the maximum height the object reaches? When does it hit the ground?
How long does it take the object to reach its maximum height?
What is the maximum height the object reaches? When does it hit the ground?
Answers
oobleck
as with all quadratics ax^2+bx+c, the vertex (max or min) is at -b/2a
The max height is c - b^2/4a
since s = 16t(9-t) the roots (where s=0, that is, the object is on the ground) are at t=0, 9
don't forget your general knowledge about parabolas when you are confronted by the equation ...
The max height is c - b^2/4a
since s = 16t(9-t) the roots (where s=0, that is, the object is on the ground) are at t=0, 9
don't forget your general knowledge about parabolas when you are confronted by the equation ...