00:01
In this example, we're doing some quick vector addition.
00:04
So what we have is we walk for a distance of 1 ,239 meters east and then 157 meters south.
00:13
We take a total time of 28 minutes.
00:16
So what we want to do is compute the magnitude of the average velocity.
00:20
So first, we're going to need to use vector addition to determine our total displacement.
00:24
And then we're going to need to use a relationship between displacement, time, and velocity to determine the velocity.
00:32
So let's set up our system.
00:34
So let me set up a little coordinate grid.
00:36
And i'm going to say we start at the origin, so right in the middle here at 0, 0.
00:43
This is going to be my positive x or east direction.
00:47
This will be positive y or north.
00:50
So we have two steps to our journey.
00:53
First, we go, and i'll call this vector a.
00:57
So a, we go for a distance of 1 ,239 meters.
01:09
And that's directly east.
01:11
So that's going to be in the positive x direction.
01:15
Ok, so that's our first leg.
01:17
This will be vector a.
01:21
Ok, then we turn and we walk 157 miles directly south.
01:28
Ok, so this will be vector b.
01:30
We go for 157 meters.
01:34
Did i say miles before? i meant meters.
01:36
And that's going to be in the negative y direction.
01:41
Ok, so let's draw that in our little plot.
01:44
Ok, so then we stop here and we go like this b...