0:00
Hi there.
00:01
So for this problem, we are told that how fast must a meter stick be moving if its length is measured to shrink by the 20 % of its original length.
00:14
So we're going to have that the length that is going to have this meter stick is going to be equal to 0 .25 times its initial length.
00:30
L sub 0.
00:31
Now, in this case, we are working with the length contraption that is a consequence of general relativity, special relativity, sorry.
00:44
So what we are going to use is the equation for length contraption that states that the length of a moving object is going to be equal to its initial length divided by the lawrence factor.
01:01
That is 1 minus the speed of this object divided by the speed of light square.
01:09
So what we are going to do in here is to solve for this speed because that's what we want to obtain from this.
01:16
So the first thing that i'm going to do is to elevate both sides of this equation to the square.
01:22
So we can get rid of the square root.
01:25
So we're going to have the length to the square is equal to the initial length to the square.
01:31
Times 1 minus the speed square divided by the speed of light square.
01:37
So now we start solving for the speed.
01:42
As you can see, we can pass this to divide to the other side...