Question

You are traveling in a spaceship at a speed of 0.70c away from Earth. You send a laser beam toward the Earth traveling at velocity c relative to you.

What do observers on the Earth measure for the speed of the laser beam?

Answer 1

@ganeshie8 i think this is 1 x c but im not sure about it, can you help me out with this please

Answer 2

so the actual answer would just be 1 bc it states in the problem v =_______ x c

Answer 3

One of the axioms of special relativity is that the speed of light is the same in all reference frames, so yes you're right that the observers on Earth will measure its speed as c

Answer 4

wait so its only 1 not 0.70 bc its multiplied to c

Answer 5

I'm not sure what you mean by that.

We're talking about the speed of a laser beam (a form of light). Light travels at the same velocity regardless of the velocity of its source or the relative velocity of who's measuring it.

Answer 6

so if the light speed is the same in all reference frames than would 0.70c to the observer or would it just be 1 I am getting confused there

Answer 7

since it says v = ______ x c would I do this instead

1 x .70 and I would get .70

or this instead

3.0x10^8 (.70) = 210000000

Answer 8

I think he was saying that no matter what frame it is, light will travel at the same speed.