What is Special Relativity (3)

Do the formulas in solution 3 look familiar?

Do they remind you of something about Special Relativity?

It seems our clock fixing formula in solution 3,  
and the time dilation formula in Special Relativity,  
look very alike.

In fact, our formulas from solution 3 represent the two most famous conclusions of Special Relativity:

Time Dilation, slower clock 2

and Length Contraction. shorter ruler 2

Is this a coincidence? Absolutely not!