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Jul
27
reviewed Close How to find this torque?
Jul
27
reviewed Leave Open How to find the final momenta of these objects?
Jul
27
comment How to find the final momenta of these objects?
You have to be more specific. Carefully work through the steps I mention. They are not obvious if you've never done this before. Exactly where do you get stuck?
Jul
27
comment How to find the final momenta of these objects?
@archipelagoS You have $v=v_1+v_2$ and $v^2=v_1^2+v_2$. Two equations. There are two unknowns, which? Which want do you want to solve for first (does not matter)? Then solve for the other. Note: There are two solutions, because one of the equations is quadratic. What does that mean physically?
Jul
27
comment On the coordinate independence of general relativity
This is not even a "link-only" answer, because there is no link...
Jul
27
comment The magnetic polarity of earth?
@ACuriousMind The homework close reason clearly states the "show some effort". I suppose this was community determined.
Jul
27
reviewed Close The magnetic polarity of earth?
Jul
27
reviewed Close How to get funding for research on something that can revolutionize the quantum world!
Jul
27
reviewed Close Variation of the action respect to the metric, integration by parts, variation of ricci tensor
Jul
27
revised Does the universe have an edge/boundary/barrier? If yes, what is at the edge?
added 14 characters in body
Jul
27
reviewed Close How was Newton able to guess that gravitational force is inversely proportional to distance squared?
Jul
27
comment How to find the final momenta of these objects?
@JohnRennie Although your solution is the quickest and most obvious route, I also always let students derive it by writing down explicitly all the equation, such that they conclude themselves the CoM-frames can be very helpful.
Jul
27
comment How to find the final momenta of these objects?
@archipelagoS Both options 1 and 3 can be correct. 1=complete inelastic (sticking objects) and 3=completely elastic.
Jul
27
comment How to find the final momenta of these objects?
@archipelagoS You don't. It is weird to substitute an known ($v$) with an unknown. It is better to substitute $v_1=v-v_2$ and calculate from there without assumptions.
Jul
26
reviewed Close Mathematical proof of the Second Law of Thermodynamics
Jul
26
reviewed Close Why do we say that the electric forces are stronger than gravitational forces?
Jul
26
reviewed Close Can statistical mechanics explain the second law completely?
Jul
26
reviewed Close How do geocentric theories explain seasons?
Jul
26
reviewed No Action Needed Bernoulli's principle on a curve ball
Jul
26
reviewed Approve suggested edit on Electric Field for a hollow sphere with point charge