Lesson Problem on a ball thrown vertically up from the top of a tower

Problem on a ball thrown vertically up from the top of a tower

Problem 1

If our parabola is written in the general form s(t) =  with a = -16, b = 64 and c = 60, then the maximum height will occur at t = .

By plugging in the values for "b" and "a", you find the time moment 

t =  = 2 seconds.

Max height occurs after 2 sec, so replace t with 2 in the original equation

s(t) = ,

s(t) = ,

s(t) = 144 ft is the max height.

When the ball hits the ground, s(t) = 0, therefore

 = .

Simplify, divide by -16, then we can factor

 = ,

(t-5)(t+1) = 0.

The positive solution is what we want here (the negative is not).

t = 5 sec to hit the ground