what is the most important diffrence between potential and kinetic energy?

Answer 1

Potential energy is stored energy, and kinetic energy is energy in motion

Answer 2

Kinetic energy is energy released from Potential.
EXAMPLE: Roller Coaster
When it goes up, it gains Potential Energy
When it goes down, it releases all the Potential Energy in Kinetic Energy!!

Answer 3

Potential energy has to do with WHERE something is in a field.

Kinetic energy has to do with how fast it's moving.

Answer 4

Here's an analogy that might help you to see the most important difference(s) between potential and kinetic energy. It also includes an analogy to the role of friction in dynamical problems involving potential and kinetic energies.

Potential energy is like money in an interest-free Bank account, at a given location. While it's still there, it's not being used, but it's comforting to know that you could draw on it if you wanted to do so.

Kinetic energy is like some of that money that's been drawn out of the Bank, and is now moving around town with you.

If you don't SPEND any of that money, the sum of the money in the Bank and the money in your pocket remains the same. That "Conservation of Money" is analogous to the "Conservation of Energy." What's more, at any time you can decide to put some or all of the money back into the Bank. No matter when you decide to do this, the sum of what's in your Bank and what's in your pocket will remain the same, equal to what you started out with.

However, if you SPEND some of that money as you move around town, it's now gone from your pocket. An obvious consequence of that is that the sum of what's still in your Bank and what's now in your pocket is LESS than you started out with. One thing that is analogous to that "spending" of your money is FRICTION. The role of friction in the world is that it "spends" your kinetic energy, thus removing some of your kinetic "money" that you withdrew from the Bank.

Unfortunately (sigh!) this is a one-way process, and the total amount of money now available to you is less than you started out with. Even if you put all that you now have back into the Bank, it won't be as much as the initial amount. If we use gravitational potential energy as an example, that means that with kinetic friction, something that fell from a great height and was redirected smoothly back upwards (e.g. along a wire with SOME friction associated with it) will not make it back to the same height --- its later maximum height will necessarily be lower than it started out from.

In case this all sounds rather depressing, there's one sense in which the "spending" of kinetic money has been extremely important for the existence of our world and of humanity.

When pre-stellar material "falls together" from very large distances, it's converting potential energy into kinetic energy. If all the particles retained the same total energy (P.E. + K.E.) that they started out with, they could fly back out to where they started from. Then STARS COULD NEVER FORM!

However, two important things happen:

1. Stuff collides, and in so doing the kinetic energy is randomised --- in other words, things get hot. (This isn't, so far, like friction --- the TOTAL energy is still the same.) However,

2. HOT things RADIATE --- and THAT radiation goes off into the wild blue yonder, very quickly if the stuff is still transparent, much more slowly if it has become opaque. But however it happens, THAT represents another one-way conversion of some of your energy (kinetic "money") into a form you can no longer get back.

Consequently, BOUND, HOT gravitational structures are now INEVITABLE. What's more, the more they radiate, the hotter they become ***** until eventually they become so hot that they can have nuclear reactions take place inside them. They can then tap the energies residing in nuclei, which can provide much more energy than was previously available from gravity alone. That leads to a very long-lived phase as main-sequence stars. (The Sun is now approximately half-way through its main-sequence lifetime.)

I hope that you now see not only how important the conversion of gravitational potential energy into kinetic energy is, but also how important for us the draining away of some of that kinetic energy is (by the "frictional losses" associated with radiation removing energy from the system). That's ultimately why the stars, our Sun, and our solar system exist.

***** Notice that your coffee cup never behaves like this when left standing on your kitchen table. As your coffee cup LOSES ENERGY, IT gets COLDER. But as gravitationally bound stellar material LOSES ENERGY, IT gets HOTTER !! This may seem quite bizarre at first sight. The ultimate reason behind this very odd behaviour is that Gravitation is a NEGATIVE ENERGY FIELD, and there's ALWAYS more of that energy there to tap, by becoming smaller. That seems very odd and counter-intuitive because we're just not used to encountering negative energy fields in everyday life.

So, you see that your innocent question has led us into (almost literally) very deep scientific waters!

Live long and prosper.