Another fairly simple topic is LOL charts. We are very familiar with these because we did these freshman year and then in chem again last year. So I didn't really struggle with these. Basically you identify what's in the system. Then you identify what energies are present at that moment of time. For instance, in number one in position the cart is not moving. It has elastic energy from the spring, and then in position b the cart is both in the air and moving. This means it has both elastic and kinetic energy. Basically how I think of it. Is moving?? If yes then it has kinetic. Is it off the ground??? If yes, then it has gravitational. Is there a spring involved in that moment??? If yes, then it has elastic. #2 on the paper is a little tricky. The idea of Work is introduced. The problem looks identical, except it says to exclude the spring from the system. Since there is no spring in the system, you can't account for the elastic. So how did you get from point a to point b?? The energy had to come from someone. You call this work. And as you see, the last problem involves dissipated because you need to account for friction. Note on those charts, dissipated is not on the first LOL chart at position A but only the one at position b. The energy could only go towards the friction if it is moving, therefore it would not make sense to have dissipated on the beginning. Overall this was just a big review from freshman year, so I found this fairly easy.
