I was reading some articles about Casimir effect. It turns out that some virtual particles are created and suddenly disappears amd that these particles can exert a pressure on the plates. It seems that this creation breaks energy conservation law, but it cannot be.I would like to know which...
I would like to fine the kinetic energy of a cone that rotates around its symmetry axis.
I consider that the cone is formes by infinite cylinders with different radius and infinitesimal height. I end up with this result:
K=1/4w^2R^2hM
where w is the angular velocity R the radius h the height and...
If there is a rotating wire in a constant magnetic field what is the direction of the induced current ?
The problem is the direction of the area vector which is arbitrary, if it is parallel to the magnetic field the current will flow in a direction, if it is anti-parallel it will flow in the...
I guess C because at infinity we will have PE=0 and KE> 0 or equal to zero. As the rocket has not the tendency to move to infinity we conclude that
PE+KE <0
We know that Lorentz Force is a centripetal force so:
$$qVBsenx=m\frac{v^2}{r}$$ and the value of V is constant (but not the direction)
But if we write:
$$qvBsenx=m\frac{dV}{dt}$$
we obtain that v is exponential.
What is wrong ?
We know that objects like plastic become negative (with rubbing) but what will happen if we rub plastic and plastic, one of them will become positive which one ?
Let's say that I have a spoon and a cup of coofee, I stir it with the spoon does its temperature decrease or increase ? (There is friction force so a bit of energy should turn into heat but it's strange).
Can someone explain me what is the connetion between centrifugal force and weight force thanks ? In which situation should I use the centrifugal force (that is a fake force) ?