Elastic or inelastic collision?Ball A with a mass of m, whose velocity is 0.8660254c , hits a static ball B with a mass of m (aligned with the center of the ball). What are the final velocities of A and B?
Elastic collisionElastic or inelastic collision?
OK. Then it's pretty straightforward. They exchange momentums.Elastic collision
Can you give your answer directly?OK. Then it's pretty straightforward. They exchange momentums.
Please post your answer first, Tony. If you have an answer, that is.
Remember the problem you had with your previous relativistic scenario? You couldn't solve it yourself.
Are you able to solve your own problem here? Or are you asking for help?
Is this your homework, Tony?
Also, is this a straight-line collision, or a glancing collision? Remember how you underspecified your scenario in a previous thread, Tony? Yet here you are again, failing to include important information in the scenario description.
If you leave out necessary information, how do you expect us to help you with your homework?
James R, my question has been clearly stated (aligned with the center of the ball).Ball A with a mass of m, whose velocity is 0.8660254c , hits a static ball B with a mass of m (aligned with the center of the ball). What are the final velocities of A and B?
James R, can you give an answer? I don't really know the answer, it looks like you know what the answer is, can you just share your answer here?Can you solve the problem, Tony? Hint: it's an easy one.
If this were simple Newtonian mechanics, i.e. at relative speeds <<c, what would be the answer, Tony?James R, can you give an answer? I don't really know the answer, it looks like you know what the answer is, can you just share your answer here?
OK, I can give the answer: Suppose the speeds of A and B after the collision are v1 and v2 respectively.If this were simple Newtonian mechanics, i.e. at relative speeds <<c, what would be the answer, Tony?
If A had velocity V and B had velocity 0, then after the collision A has velocity 0 and B has velocity V.Can you give your answer directly?
What are the velocities of A and B?
Ball A with a mass of m, whose velocity is 0.8660254c , hits a static ball B with a mass of m (aligned with the center of the ball). What are the final velocities of A and B?
Janus58, Could you give an answer?
That is correct, Tony. There is no need for relativity in solving this simple problem.
Have you ever thought about such a problem, the mass of A is measured when A is stationary, now A has a velocity of 0.8660254c, according to SR, the mass of A is no longer m, and the momentum of A is no longer mv , the kinetic energy of A is no longer 1/2mvv. What do you think? Is there really no need to consider SR here?If A had velocity V and B had velocity 0, then after the collision A has velocity 0 and B has velocity V.
Why not do the algebra again, using γ, then?Have you ever thought about such a problem, the mass of A is measured when A is stationary, now A has a velocity of 0.8660254c, according to SR, the mass of A is no longer m, and the momentum of A is no longer mv , the kinetic energy of A is no longer 1/2mvv. What do you think? Is there really no need to consider SR here?
Why not do the algebra again, using γ, then?
That's why I'm here, because I really don't know how to use SR to calculate this problem. If you can give an answer, you can share it here directly, you are always full of wisdom.That is correct, Tony. There is no need for relativity in solving this simple problem.
If you are actually curious, Wiki has a good explanation, just look up "Elastic Collision".That's why I'm here, because I really don't know how to use SR to calculate this problem.
There is actually a derivation at the site Origin refers to, using the SR formulae for energy and momentum. The trick seems to be to use the centre of momentum frame of reference. That gets you away from the rather hideous calculations you would get if you tried to expand γ. Here is the link: https://en.wikipedia.org/wiki/Elastic_collision.That's why I'm here, because I really don't know how to use SR to calculate this problem. If you can give an answer, you can share it here directly, you are always full of wisdom.
“The trick seems to be to use the centre of momentum frame of reference”, this method seems to greatly simplify the calculation, but when the reference frame changes, does the mass m of A and B also need to change? When A and B are stationary relative to the earth, we measured their mass as m, and now the reference system is no longer the earth, so is their mass still m?There is actually a derivation at the site Origin refers to, using the SR formulae for energy and momentum. The trick seems to be to use the centre of momentum frame of reference. That gets you away from the rather hideous calculations you would get if you tried to expand γ. Here is the link: https://en.wikipedia.org/wiki/Elastic_collision.
Of course not. Nothing from that analysis suggests anything of the sort.is the earth the absolute reference system in the universe?