Here are a couple of conceptual questions from my cumulative review.
1. Is energy released or absorbed when a gas changes to a liquid?
2. If a yo-yo is being whirled around by its string in a vertical circle, does the string apply an outward force or an inward force?
The Attempt at a Solution
I think that energy is released when a gas changes to a liquid, and I believe that the string is applying an inward force.