Very quick question, does a magnet contain energy? The general consensus seems to be, it does not. And this is generally confirmed by the fact that it would break the first law of thermodynamics. Whatever the hell that is (joke:)
The reason I ask is because a) I'm no genius and b) because I'm perplexed. So maybe some of you smart people could help me out please.
Here's the scenario;
Now, if I took, oh I dunno, say a metal ball and lifted it say six inches. I have converted some of my man boob calories into energy that is now stored in the ball. When I release it and it drops to original level, the energy is released. Makes sense.
Now if I took the same metal ball and rolled it along the ground, it would continue to roll until the kinetic energy was depleted, through friction and stuff like that.
Now if I take the same ball and roll it along the ground, but this time with a magnet suspended 6 inches from the ground and directly in the line of movement. The magnet is strong enough to attract the ball and is therefore lifted 6 inches and sticks to the magnet. Where has that energy come from? It can't have come from me putting the magnet there, as once I put the magnet back on the ground, I have released that energy.
As I said, I'm not smart, nor educated, just been pondering this question for a couple of days.
Would be great if you could allow my brain to get back to menial tasks.
Thanks
Best Answer
The person before has put an answer which might be more complex and answer your entropy question. however to answer your magnet issue in a simpler way concentrating on your metal ball might be more fruitful for you.
What you have is 2 fields here at work both with similar properties gravity and magnetism. let me ask you this, why does your ball fall when you raise it 6 inches and let go? gravity. the earth (and conversely the ball) attract each other. Your ball wants to always fall to the lowest energy state it can and the closer the ball and the earth are to each other the lower the potential energy as you rightly said. lift the ball and you spend your energy to move it further away and give it the gravitational potential energy. Release it and that energy is converted back into kinetic energy of movement as the ball falls to the lower gravitational potential energy state ie. closer to the earth.
your magnet is much the same. the magnet attracts the ball as the earth does, except it is an electromagnetic force not a gravitational one and it is stronger than gravity. your ball wants to fall to a lower magnetic potential energy state too and this is closer to the magnet. So therefore pulling the ball away from the magnet your providing energy to move it to a higher potential energy state and it wants to be in a lower one next to the magnet, hence attraction. now this is not as intuitive as gravity is always there and your magnet is not. but really when your magnet is not there its in the higher potential state it just cant get to a lower one until the magnet is present.
combine the two together and in opposite directions ie gravity pulling the ball down and the magnet pulling it up it will go towards the strongest. why? well because it will loose more magnetic potential energy than gravitational because the magnet is stronger. so whilst you see it fly 6 inch off the table its actually in a lower energy state than being six inches closer to earth.
hope this helps :)