Question

Time-Reversal invariance

Justify whether Diffusion breaks time-reversal symmetry. (Hint - consider the diffusion equation.)

Answer 1

Answer :-

Under free fall due to gravity

When upward direction is positive.

Now, If you reverse time, the sign of V-yo changes as well.

Explanation:-

Let us say you vedio tape the ball falling.

* Now, you look at the tape, run it for a while and then press pause.

* At this point, the ball has a certain height (say Y) and a velocity in the downwards direction and the acceleration does not care about you vediotaping and always is negative. can think about the case where the initial velocity was also negative this will just make the paused instant velocity even more negative.