Question

explain the differences and similarities between classical and relativistic mechanics.

Answer 1

Answer :

Classical physics is causal; complete knowledge of the past allows computation of the future. Likewise, complete knowledge of the future allows precise computation of the past. (Chaos theory is irrelevant to this statement; it talks about how well you can do with incomplete knowledge.) Not so in quantum physics. Objects in quantum physics are neither particles nor waves; they are a strange combination of both. Given complete knowledge of the past, we can make only probabilistic predictions of the future.

In classical physics, there is an "in-principle" determinism. If you had N atoms of neon in a gas canister, and you knew the position, and momentum of every one, in principle you could describe the history fully for all time.

In classical physics, things like electrons and atoms were supposed to be treated as strictly particles, and things like light and other forms of electromagnetic radiation treated strictly as waves. (It turns out that there are a lot of things that happen with light and electrons that cannot be properly explained in classical physics!) Classical physics. Each particle has an exact position and momentum. In quantum physics, there properties such as position and momentum that are NOT measurable to any accuracy, independent of the process of observation. Specifically in the case of position and momentum, there is a limit on how accurately you can measure both at once.

In classical theory, a body always chooses the least action path and there is only one path. In Quantum theory, a particle also always chooses the least action path and it chooses multiple least action paths simultaneously.

We can determine position and velocity of a particle simultaneously with great accuracy in Classical Physics. Quantum Physics follows the Heisenberg Uncertainty Principle.

Classical Physics is applicable to macroscopic particles. Quantum Physics is applicable to microscopic particles.