#Skiing is an excellent physics lesson in the difference between Potential Energy and Kinetic Energy. Also teaches conservation of energy.

When entering a ski resort, your (the skiers) body is like a big potential energy battery. When you get on the chair lift, the energy powering the lift is converted into potential energy of your body now sitting at the top of the run. You have now been “charged” with (say)2000 vertical feet of (say) 200 lbs of potential energy.

Now, you need to get down the hill. You can either expend all of it all at once (splat!) or better, exert kinetic energy against it a controlled manner.

As you ski down the hill, you are exerting your own kinetic energy (muscles) which is pushing against the release of the potential energy of your body sliding downhill. Most of that kinetic energy is lost as friction/heat. As it occurs in snow, nobody notices.

The amount of energy used to slow yourself down is exactly the amount of potential energy the chair lift transferred to bring you up hill.

Actual physicists are welcome to inform me where I got things entirely wrong.