00:02
While this problem may seem daunting, all we have to do is actually look at it in a different light.
00:07
So we know what the initial velocity of the ball is from the ground, and it's asking how much time it takes to pass a branch on the way up and then pass it again on the way down.
00:20
So what we need to do is we need to figure out how fast the ball is going when it reaches the branch, and then reset our system so that it's just looking at the time between the ball, the branch on the way up and when it comes back down.
00:35
So to solve for how fast it's going when it passes the branch, we use the information that we're given and the equation b squared equals initial velocity squared plus two times a times x.
00:45
We plug in all of our numbers and when you do out all the math including finding the square root for b, you find that the speed of the ball is 9 .37 meters per second when it passes the branch.
00:58
What we're going to do is we are now going to use that velocity as our initial velocity.
01:04
And we're going to reset our frame of reference here to just when the ball passes the branch in the beginning and then at the end.
01:12
Because we're resetting this and we're saying that the initial velocity is 9 .37, that speed at the branch, we can actually now redefine the position of the branch to be zero, because that's going to be easiest for us...