What is Special Relativity (2)
Normally, the story would end here.
But unfortunately, this swimmer is no other person than your boss. He is very confident with his swimming skills. If you told him that his average speed is less than c, you will certainly get yourself into trouble. So you tell him that something is wrong with the clock or the ruler, and ask him to try again after you have fixed it.
But how do you fix it?
Mathematically, there are numerous solutions. But in reality, we will take one of the following three approaches:
Use a slower clock, use a shorter ruler, or change both a little bit.
Solution 1: A slower clock
Solution 2: A shorter ruler
Solution 3: A slower clock and a shorter ruler
Here the tfix and lfix are the adjustment rate of the clock and ruler, respectively.