00:01
This question gives us a displacement, and it says that the displacement is minus 16t squared plus 96t plus 112.
00:12
And the first part of the question says, what's the object's velocity when t is equal to zero? so when t is equal to zero, what's the v of t? so in order to find v of t, we have to take the derivative of s.
00:23
So it's going to be minus 32t plus 96.
00:29
And so v of zero then is going to be 96.
00:33
All right so that's my answer for part a and it's in feet per second for part b it asks me what's the maximum height so the maximum height happens when the velocity is equal to zero right when b is equal to zero so i take minus 32 t plus 96 and equal zero that means that 32t is 96 which means that t is three okay so if t is three then we find s of three that will give me my maximum height so that's give me minus 16 times 3 squared plus 96 times 3 plus 112.
01:15
And if you do that out, you get 256 feet.
01:20
So that is my maximum height.
01:22
And it happens at t equals 3.
01:25
Okay.
01:26
And then finally it says, what's the velocity of displacement is zero? so if you look at s equaling zero, we've got to solve minus 16 t squared plus 96t plus 112.
01:40
Okay, so i want to know, first of all, can i divide everything by 16? because if i can, this becomes much easier...