00:01
So question one shows waves traveling toward each other.
00:08
After one second, they're each going to move one step on the x axis, because they're traveling one meter per second.
00:24
So x is meters.
00:29
Y is going to be the displacement in centimeters.
00:38
So they're going to move one.
00:42
So the leftmost pulse used to start at zero and end at four.
01:00
So now it's going to start at one and end at two, three, four, five.
01:09
The middle was at two, so now the middle is going to be at three.
01:14
And so there's the leftmost pulse moved one space.
01:21
The rightmost pulse is going to, used to be centered at eight.
01:26
Now it'll be centered at seven.
01:28
One, two, three, four, five, six, seven.
01:37
Okay.
01:38
So this is nine, seven, five.
01:43
Three, one.
01:48
Okay, we need to do this to t equals six.
01:52
So right now i've got t equals one.
01:56
So let's try this again for t equals two.
02:01
That one was very simple because there was no superposition.
02:11
The two images, the two wave did not superimpose upon each.
02:18
Other.
02:19
T equals two.
02:23
So we have both of them moving over one.
02:29
So let me make all these lines.
02:35
Six, seven, eight, nine.
02:39
The red one's now going to start at two and it's going to go up to four.
02:50
And the green one is going to start at eight and go down to six, like this.
03:05
However, after those points, i'm going to create a new blue figure.
03:14
After those points, we would have to take this and add it to this.
03:23
And so i see right here that they're both at one half, both the red and the green.
03:32
One half plus one half is one.
03:35
As a matter of fact, if we take anywhere on here, this point plus this point is one.
03:42
This point plus this point is one.
03:46
So the new wave is in blue here looking like that.
03:56
A plateau.
04:00
Okay, let's make another one.
04:01
This will be t equals three.
04:11
One, two, three, four, five, six, seven, eight, nine.
04:17
T equals three from negative one to positive one.
04:26
Okay, the red one is going to move over to three now.
04:32
And it would normally look like this.
04:47
The green one would move over one.
04:55
So i'm thinking they'll be in the same spot.
04:59
But let me see.
05:00
If red moves over one and green moves over one, yeah, they're going to be in the same spot.
05:06
So the green one is going to be the same as the red one.
05:11
And so we just add everything together.
05:15
1 plus 1.
05:20
This is 1 here.
05:27
1 plus 1 is 2...