00:01
So now we have a model.
00:02
We know that the distance in feet that an object falls is 5t plus 16 t squared in feet.
00:12
And we want to know when will the object have fallen 74 feet.
00:18
So we want d to equal 74 feet.
00:23
So we're going to set our equation equal to 74.
00:29
And if we have to use a grapple, we could use a graph or we could use a graph to find the intersection.
00:33
But why don't we just set it up like so.
00:41
Now, i could try to factor this, but i'm not going to try to.
00:45
Let's go right to quadratic formula.
00:47
So we're going to have the opposite of b plus or minus the square root of b squared minus 4 times a times c, all over 2a, which is 32.
01:04
And let's get what that part that discriminated is.
01:07
25 minus, and that's going to be 64 times negative 74...