Ah yes, now we're back to using energy as a shortcut to solve problems that would be annoying bummers if we had to use kinematics on them.
OOPS! To create playlists you must logged in.
If you do not have an account, you should get one, because it is awesome! You can save a playlist for each test or each chapter, and save your "greatest hits" into a "watch right before the final" list (not that we recommend cramming, but when in Rome...)