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seen Feb 22 at 9:32

Mar
27
awarded  Nice Answer
Jan
15
awarded  Yearling
Jul
12
answered Velocity is “Distance/Time” in a particular direction OR simply “Displacement/Time”?
Jan
15
awarded  Yearling
Aug
29
answered What's the meaning of dimensionality?
Aug
26
comment Physical meaning of the sign basis in quantum mechanics
@user1247: After an ideal measurement the atom is in the state you measured, that's how an ideal measurement is defined. Before the measurement it probably wasn't.
Aug
26
revised What are the units of the quantities in the Einstein field equation?
edited body
Aug
26
answered Physical meaning of the sign basis in quantum mechanics
Aug
26
revised Physical meaning of the sign basis in quantum mechanics
fixed formatting and a typo
Aug
26
suggested suggested edit on Physical meaning of the sign basis in quantum mechanics
Aug
26
revised What are the units of the quantities in the Einstein field equation?
I forgot the cosmological constant
Aug
26
revised What are the units of the quantities in the Einstein field equation?
fixed a mistake
Aug
26
answered What are the units of the quantities in the Einstein field equation?
Aug
25
comment Why can't electromagnetic radiation from magnets be used for apparent perpetual motion?
@orokusaki: If I understand your setup correctly, then yes, that should work. You are moving the magnets orthogonal to the force, therefore you're not doing any work, and thus the magnet should be moving forever. Or in field energy terms: The fielf always looks exactly the same, just at a different position, and since you don't accelerate, there's also no radiation. However, that's no perpetuum mobile, because you don't gain energy; it's no different than the magnet moving with constant speed where there's no other magnet (that is, no magnetic field).
Aug
25
comment Why can't electromagnetic radiation from magnets be used for apparent perpetual motion?
you don't take energy from the other object, but from the field. A nice example where you can see it quite directly is the electric field of a (charged, but not connected) plate capacitor. The two plates attract each other, therefore you need energy to move them apart. There's a homogeneous field in between then, whose energy you can calculate before and after moving the plates. If you do so, you'll find that the total energy in the field has increased exactly by the amount of work needed to move the plate against the field. So the plate's potential energy actually is the energy of the field.
Aug
25
comment Why can't electromagnetic radiation from magnets be used for apparent perpetual motion?
You cannot radiade a force. You radiate waves, or you radiate particles. The magnet is surrounded by a magnetic field, but it doesn't radiate it. Note that also an electromagnet doesn't radiate (except when you switch it on or off, and ignoring the heat radiation because of the wire's resistance). And it is true that you do work (and thus change energy) if you move a magnetic object in the magnetic field, that's something different from radiating energy. When radiating, you lose energy even without objects moving. Also note that when you move objects in the field of another object, …
Apr
18
answered Building some measurement appratus that distinguish between two mixtures
Apr
18
revised Building some measurement appratus that distinguish between two mixtures
nicer (and more standard) bra/ket form
Apr
18
suggested suggested edit on Building some measurement appratus that distinguish between two mixtures
Apr
15
answered What's wrong with this equation for harmonic oscillation?