I've been hunting around online but have found only long-winded explanations of the speed of light in non-intertial or accelerated reference frames, which mostly relate to gravity. I'm looking for just a straightforword treatment dealing more specifically with traveling acceleration and not necessarily gravity. My understanding is that if I'm traveling at a constant velocity .3c relative to my friend Al and I shine a flashlight, I will see the light move away from me at c. Al will also see the light travel at c, and will see me traveling at .3c in the direction of the light. Here's my question...If I suddenly accelerate from .3c to .5c over a ten second period, and then proceed from thereon at .5c, what is the experience of me and Al? Does either of us measure the speed of light to change in this situation, that is, during the 10 second period of acceleration? If so, why and how? If not, why not and how not?