00:01
So for this problem, we're given the graph of velocity, we want to find average acceleration from two seconds to nine seconds.
00:10
So to do this, we look at the velocity at two seconds, which we see is zero.
00:16
So it's going to be v of average acceleration will be v of 9 minus v of 2.
00:21
That's our delta v over the delta t.
00:24
So that's going to be 9 minus 2.
00:27
So at 2, our velocity is 0, but at 9, our velocity.
00:31
Is 10.
00:33
So we're going to have 10 minus 0 over 9 minus 2, which is 7.
00:37
So we'd get 10 7th meters per second square.
00:40
Then we want to know the acceleration of the car at four seconds exactly.
00:46
Well, that's going to be the slope.
00:48
So we need to look at points surrounding at this point.
00:54
We see that if we look a little bit below, so say 3 .5, we have the point 3 .5 and looks to be about 7...