00:01
Okay, so for this question, we know that there are two spaceships, which is a and b, they are approaching to each other according to an earth observer.
00:09
Spaceship a has a speed of 0 .40c, and spaceship b has a speed of 0 .50 c.
00:17
If we consider spaceship a is moving in the positive direction, that means spaceship b is moving in the opposite direction, which is negative direction.
00:25
And that's why i give the speed of, the velocity of the spaceship a is positive direction.
00:31
The 0 .40c and the velocity for the spaceship b is negative 0 .50c.
00:37
So the question was asking us what's vba which is the speed of b that is relative to spaceship a? well we know if we come out the equation which is vba can be equal to vea plus ve and over 1 plus vea times vbe over c square.
01:13
The reason why i use vea in this case because the objects will consider is the spaceship a.
01:20
So spaceship a is the relative point we'll consider it.
01:23
Okay.
01:25
So that's why i switched the order of va to vea...