00:01
Okay, so we have this rocket ship that's traveling over here.
00:05
It's got a clock that's putting out ticks every one and a half second.
00:12
To the clock, the delta x is zero because to anyone on the ship, it feels like they're at rest.
00:19
And they're just seeing this clock going tick, tick, tick.
00:23
So their delta x is zero.
00:27
So then we have our lorenz transformation.
00:30
So we got this.
00:31
Then our delta x is zero.
00:40
So delta t prime is gamma delta t.
00:45
Here's delta x prime.
01:11
So our answer to part a.
01:23
So part b is length contraction.
01:32
And the formula for that looks like this.
01:40
So the reason for this, you actually have to derive this.
01:45
You have to think carefully because the events for measuring the length of the spaceship in the unprime frame, there's actually two events.
02:00
They have to look at both ends of it at the same time and say, gee, what's the length in between? but those two events occur at different times in the prime frame.
02:13
And you have to take that into account.
02:16
So that's how there's a one over gamma here.
02:18
You can look at any physics book, any relativity text, and it'll tell you about how to do that.
02:28
So our l is 100 divided by our gamma...