A few days ago
Gabe

Height of a Ball? College Algebra Math?

I need help on how to set up this problem. If a ball is thrown directly upward with a velocity of 40 ft. per sec., its height (in feet) after t seconds is given by y=40t-16t squared. What is the max height attained by the ball??

Top 3 Answers
A few days ago
James H

Favorite Answer

f(x) = -16t² + 40t is the equation in question. Since it is a quadratic, we can find the Axis of symmetry by calculation. the line is found where t = -b/(2a) . this gives you t = (5/4) so the maximum height is when the time is 1.25seconds. plug that in place of t and get a maximum height of 45ft. I did this off the top of my head so you might want to double check.
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A few days ago
chasrmck
It’s position at initial and final point is 0

0=40t-16t²

0=t(40-16t)

t=0,5/2

since the equation describes a parabola the vertex(maximum) should occur halfway between the zeros or at t=5/4

y=40(5/4)-16(5/4)²

=50-25

=25 ft.

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A few days ago
Anonymous
40/32 ft is maximum time

plug that in to find max height

y = -16t^2 + 40t is the equation

take the derivative of that and equal it to 0 to find when the function isnt changing anymore (maximum or minimum of a function)

y’ = -32t + 40

0 = -32t + 40

32t = 40

t = 40/32

y = -16t^2 +40t (original function, now plug in T to find max height)

y = -16(40/32)^2 + 40(40/32) is the answer, and I have no intention of calculating the exact number 🙂

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