00:01
In this problem, we're going to talk about the principles of relativity.
00:04
So there are two general principles that we have to follow when we're dealing with a special relativistic problem.
00:11
The first one is that the laws of physics are the same for every inertial reference frame.
00:16
So it doesn't matter what inertial reference frame you're in.
00:21
As long as you're in an inertial reference frame, all the lots of physics have to apply.
00:26
So, for example, the maxelose equations remain the same.
00:30
The laws of newton must remain the same, etc.
00:36
So there is no preferred inertia reference frame.
00:41
The second principle of relativity is that the speed of light is the same for all inertial reference frames.
00:48
Okay, so this is very interesting because it doesn't matter if you are at rest with respect to the earth or if you're moving very, very close to the speed of light.
00:57
If someone sends a laser towards you, you're going to see the laser traveling with the speed of light, 3 times 10 to the 8 meters per second, no matter your speed.
01:17
Okay.
01:18
So in our problem, we have proton that decays.
01:25
Actually, it doesn't decay...