00:01
And this problem we're told that a particle follows the trajectory x.
00:04
Of t.
00:05
Is one quarter t cubed plus two t.
00:09
And y is a function of t.
00:10
Is 20 t minus t squared with 10 seconds and distance in centimeters.
00:15
We first want to find what the particles maximum height is and then we want to figure out when the particle hits the ground again, how far from the origin doesn't land.
00:25
So what i've done is i've made a lot of this function here.
00:28
So you can have a look at it and so we can see a.
00:31
T.
00:31
Equals zero where zero.
00:33
And we rapidly go up to our maximum value and then we slowly decay back down to the ground.
00:42
So the first thing we want to do is figure out when y is a maximum.
00:47
So we have y equals 20 t minus t squared.
00:54
So we can take the derivative of that and that is 20 minus two t.
00:58
And set that equal to zero to find out team when but here when why is the maximum is 10 seconds.
01:09
So we can plug then 10 seconds into our formula for why to get why max and that equals 100 cm...