1. Oct 13, 2012

### Yukz23

The problem statement, all variables and given/known data
Spacecraft 1 is launched from the surface of the Earth with a velocity of 0:6c (Earth
RF) at an angle of 50

above the horizontal +x axis. Spacecraft 2 is moving with a
velocity of 0:7c (Earth RF) in the x direction towards Spacecraft 1. Determine the
velocity and speed of Spacecraft 1 as measured by the pilot of Spacecraft 2.

The attempt at a solution
I'm trying to solve this and I'm stuck a bit so far all ive got is that
Vs1e (velocity of space craft 1 respect to earth) = 0.6cos50(c)
Vs2e = -0.7c

they want Vs1s2 = Vs1e + Ves2/ 1 + Vs1e (Ves2)/c^2

I'm stuck because I don't know what "Ves2" would be...

2. Oct 14, 2012

### Simon Bridge

Welcome to PF;
I can't tell either ... I hate subscripts.

In the E frame:
Craft 1 has an x and a y component.
Craft 2 only has an x component.

Use the formula on each component to find the relative velocity of frames 1 and 2.

3. Oct 14, 2012

### Yukz23

Lol Thanks,

So should I first do the formulas for the x components and the y components and then combine it..and the hypotenuse would be the answer?

4. Oct 14, 2012

### Simon Bridge

Well... one of the directions does not matter.
Remember the derivation of time dilation you did a while ago - only one of the directions counted for that too.