Posted by Jin on Monday, March 26, 2012 at 6:44pm.
the vertex of a parabola is at
x = -b/2a = -28/-32 = 7/8
h(7/8) = 19.25
If you know Calculus, this is easy
dh/dt = -32t + 28 = 0 for a max of h
32t = 28
t = 28/32 = 7/8 = .875
h = -16(49/64) + 28(7/8) + 7 = 77/4 = 19.25 ft
if you don't know Calculus, you must complete the square
h = -16(t^2 - 28/16t + ...) + 7
= -16(t^2 - (7/4)t + 49/64 - 49/64) + 7
= -16( (t-7/8)^2 - 49/64) + 7
= -16(t-7/8)^2 + 49/4 + 7
= -16(t-7/8)^2 + 77/4
the vertex of this quadratic is (7,8 , 77,4)
so there is a max of h of 77/4 or 19.25 when h = 7/8
Related Questions
algebra - A ball is thrown into the air with an upward velocity of 28 ft/s. Its ...
Algebra 2 - If an object is thrown vertically upward with an initial velocity of...
Algebra - If an object is thrown vertically upward with an initial velocity of ...
Algebra - THe function h(t)=-16t^2+v0t+h0 describes the height in feet above the...
Algebra - THe function h(t)=-16t^2+v0t+h0 describes the height in feet above the...
college algebra - When a ball is thrown up into the air, it makes the shape of a...
algebra - Library Assignment When a ball is thrown up into the air, it makes the...
algebra - when a ball is thrown up into the air it makes the shape of a parabola...
algebra - im trying to help my son i have no ida about this stuff any help would...
college algebra - When a ball is thrown up into the air, it makes the shape of a...
For Further Reading
