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Apr
14
revised Wave function not normalizable
Wrong name for dirac delta fixed
Apr
14
suggested suggested edit on Wave function not normalizable
Apr
7
comment Wave function not normalizable
Momentum eigenstates are non-normalizable in the position state space.
Mar
26
awarded  Altruist
Mar
18
awarded  Investor
Mar
7
comment Approximation of the energy for low $T$ in the early universe
@Danu There, changed it. I don't know why, I just assumed the OP was correct.
Mar
7
revised Approximation of the energy for low $T$ in the early universe
deleted 3 characters in body
Mar
7
answered Approximation of the energy for low $T$ in the early universe
Mar
7
comment Why 'max' in $hf=\phi+{1\over{2}}mv_\text{max}^2$?
@spraff Yes, basically.
Mar
5
comment How do we demonstrate that all spectral colors exist in nature?
@daniel I see. Maybe you could make that clearer in the question. And I'm sorry, the 'centuries' should've been 'decades', referring to synchrotron radiation.
Mar
5
comment How do we demonstrate that all spectral colors exist in nature?
@daniel Its not 'quite theoretical' as it is more quite real. We've been using it for centuries. However, a more prominent light source, we have blackbody radiation. The light from the Sun, stars, and light bulbs are all from black body radiation. And blackbody radiation produces continuous spectrum.
Mar
4
comment Equal and opposite reaction - forces coming in pairs - or just common sense?
let us continue this discussion in chat
Mar
4
comment Equal and opposite reaction - forces coming in pairs - or just common sense?
@MikeS Centrifugal force is a fictions force because it does not exist in an inertial frame. This is not true for reaction forces. They exist in all frames of reference.
Mar
4
comment Equal and opposite reaction - forces coming in pairs - or just common sense?
We have two charged particles, one with +q, and another with +10q. They have different masses, and are not touching. By the Third Law, we CAN understand why the forces on both objects are of same magnitude. Inertia, however, doesn't even enter the picture.
Mar
4
comment Equal and opposite reaction - forces coming in pairs - or just common sense?
@MikeS Quoting Wikipedia: 'Inertia is the resistance of any physical object to any change in its state of motion (including a change in direction). In other words, it is the tendency of objects to keep moving in a straight line at constant linear velocity' So the definition of inertia basically just says to accelerate an object, you must apply a force'. Though it may seem natural for some form of compensation to exist, you CANNOT directly deduce this compensation (Third Law) from inertia. Regarding your request for an experiment, here's a thought experiment:
Mar
4
comment Equal and opposite reaction - forces coming in pairs - or just common sense?
@MikeS Inertia only 'explains' why a force has to be applied to an object to cause it to accelerate, but does not account for the reaction force. The universe does not 'decide' to propagate any mysterious force. We, as physicists, only construct models that describe it. No one 'really' knows why the universe has this 'mysterious force'.
Mar
4
comment Equal and opposite reaction - forces coming in pairs - or just common sense?
@MikeS Your acceleration only depends on the net force upon you. Assuming the force you apply on the box is the same, then no matter how the mass of the box changes you fly backwards the same way.
Mar
4
comment Equal and opposite reaction - forces coming in pairs - or just common sense?
@MikeS As I mentioned in my other comment, you are wrong. The box really does exert a force on you. You simply don't gather a net force (friction force opposes your motion, cancelling it out), it doesn't mean the box doesn't push at you. In fact, it does push at you.
Mar
4
comment Equal and opposite reaction - forces coming in pairs - or just common sense?
@MikeS Because, imagine you were pushing it in empty space, with nothing but you and the box. Then, after you push it, you will be flying backwards. The reason this doesn't usually happen is because of friction between you and the ground.
Mar
3
comment How to obtain the distance traversed by a free falling body equation?
It was taught to me as USA-TV. Incredibly easy to memorize.