I just found out that you can do acceleration/deceleration problems in SR. I didn't know that.(adsbygoogle = window.adsbygoogle || []).push({});

The problem I was thinking of was the classic Terence/Stella problem of recent fame on this Forum. See this post by Jesse M who solves this for constant velocities:

https://www.physicsforums.com/showpost.php?p=2610219&postcount=63

Basically, Terence and Stella are on Earth. Terence stays put while Stella accelerates, to the right, say, at 7 g (about 70 m/sec^{2}s until achieving a velocity of 0.6c (or 180,000,000 m/sec) to the right and then turns around and decelerates at 7 g's until she reaches or catches up with Terence on Earth. I chose 7 g's because good pilots and reclining astronauts can take that for a while.

I don't know where to get started. I've omitted the "crusing" speed of 0.6c to keep matters simple. In other words, Stella's rocket goes out and immediately turns around to come back.

I don't know if you can use the standard v = at and s= (1/2)70t^{2}= 35t^{2}to figure alloted time and distance in Terence's frame and Stella's accelerating, then decelerating frame. I assume you have to bust her travels into two frames - one out and one in.

Please give me a kickstart. I know how to do it at "steady state" (constant v = 0.6 c) for out and back.

Do you calculate firsttfor the given parameters, thensby using thetalready calculated, and using the formula:

f X s= energy expended. Then obtain thevfor the energy by KE = (1/2)mv^{2}and then with thevfrom the energy equation (not the v = 0.6 c) and thesapply the Lorentz transforms??? I don't think so, although that would be a first good "guess."

Steve G

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# Acceleration/Deceleration in SR

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