SOLUTION: can you please help me with this equation??? For problems 11 through 13, a projectile is fired upward with an initial speed of 800 feet per second. It is given that {{{ h=-16t^2

Question 189307: can you please help me with this equation???
For problems 11 through 13, a projectile is fired upward with an initial speed of 800 feet per second. It is given that (h is the height of the ball).

What will you set h equal to in the equation to find how many seconds it takes for the projectile to hit the ground?
a. h = 0
b. h = 1
Found 2 solutions by Alan3354, nerdybill:
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
For problems 11 through 13, a projectile is fired upward with an initial speed of 800 feet per second. It is given that (h is the height of the ball).
What will you set h equal to in the equation to find how many seconds it takes for the projectile to hit the ground?
a. h = 0
b. h = 1
---------------
h is the height. The ground is h=0, so set it to zero.
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
Given:

.
a. h = 0
Set h to zero and solve for t:

.
Two possible answers:
-16t = 0
t = 0 seconds (this is at the start)
.
OR
2t-50 = 0
2t = 50
t = 25 seconds (this is at the end)
.
For this problem, the solution would be 50 seconds.
.
b. h = 1
Set h to one and solve for t:

Can't factor so you must resort to the quadratic equation.
Doing so will yield two solutions:
x = {49.9987 secs, 0.0013 secs}
.
Details of quadratic solution follows:

Solved by pluggable solver: SOLVE quadratic equation with variable

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=639936 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 49.9987499687484, 0.00125003125156198. Here's your graph:

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