length expansion

  We looked at the Ehrenfest paradox last time. There are two issues in the Ehrenfest paradox. The first assumes a disc made up of an ideal rigid body, but when rotated at relativistic speed, it ruptures. The second is that the perimeter of a rotating body is different from its length when it is stationary. In the last post I looked at the first issue, and this time I want to look at the second issue. For those who have not read the first part, I will briefly introduce this paradox. It is best to read the previous post. Below is a link to the first part. The Ehrenfest paradox part I Rotating disc and length contraction   In relativity, objects that run very fast are said to shrink in length. So the official name of this is Lorentz - Fitzgerald Length contraction. It is not 'Einstein's length contraction'. This was born regardless of the theory of relativity. Before the theory of relativity was published, several people experimented to detect ether, but the e

Hello.    Today, let's take a look at proof of length expansion using K Calculus. The first is to use the K value, the second is to modify the method of Hermann Bondi, and the third is to follow David Bohm's notation.   The first method and the second method are the ones we've already seen. I will show you again in the intention to refine your thinking, and I will look at the third method. Let's take a quick look at the meaning of the K value before that. Figure 1. Meaning of k   When John sends a light signal every four seconds, James receives a signal every four seconds. By the way, when Alice is moving from Johnson to James, Alice receives this signal at six seconds instead of four seconds. The ratio of John to Alice's signal interval is (4 seconds: 6 seconds). This can be expressed as (1: k), where the ratio is the meaning of k. It's simple. The following relation holds between the speed of Alice and k. Where v is the relat