Recent content by Minki

Yes, when you start moving the Earth's state is changed, but when you stop the Earth is returned to its original state.

Ok thanks.

Ok, so it can only be said to be conserved if you consider the original mass and the environment which the momentum was transferred to.

So it's still conserved in the original mass because whatever you transfer it to will have transferred it straight back? Even if that transfer ends up as heat?

Ok, thanks for those extra insights. Something else I'd like to get cleared up: I've read that momentum is always conserved, for both elastic and inelastic collisions. But is it still said to be conserved if there is friction? Momentum will be transferred to the particles making up the...

Yes, that's what I thought Buzz. Well I'm glad I got that sorted out, and thanks to everyone for your help.

Ok I think I get it. I see energy as mass under motion. If m or v is increased, then the energy is increased, but increasing the velocity is more significant than increasing the mass, hence the v squared. In a 100% inelastic condition, if a mass m with velocity v collides with an equal mass...

A.T: Not so much a view - more a need to understand what is happening in a demonstrable way, and to show how the math model works.

Thanks to both. Chestermiller: Yes I've done the math and it does show that KE is lost and momentum is conserved. But from a practical viewpoint, I can't see how this can be the case - for the reason that I gave about the transfer of velocity being needed to dissipate energy. russ_watters...

Yes. As far as I can see, the speed component of velocity is lost therefore the resultant vector must be smaller.

The energy component of KE is the velocity. Momentum is mass x velocity so, in a collision containing in-elasticity, if KE is lost to heat then that heat energy must have been supplied by the velocity of the object. And since velocity has been lost to supply the heat then the overall momentum...

Thanks GO1, that sorts it. The second statement did actually come from that link.

The wire in the turning coil cuts the field from a permanent magnet at right angles, which initiates electron movement in the wire. There is loads about this on the internet.

I think you question is a little unclear. Are you asking what relationship exists between mechanical and electrical energy which allows them to be interchangeable?

Hi, I'm trying to understand black body radiation but I have two conflicting descriptions (both reputable sources). Maybe both are true, but I need some clarification please: 1. A black body is a perfect emitter – it will emit equally well at any wavelength. 2. The black body re-radiates...