1. well the value may vary because of different reactions to the technology because its new to a lot of people but to younger ones its something normal and something we cant live without but with older ones its something that they have lived without for most of there life.
These energy exchanges are not changes in kinetic energy. They are changes in bonding energy between the molecules. "If heat is coming into a substance during a phase change, then this energy is used to break the bonds between the molecules of the substance
A centripetal force (from Latin centrum, "center" and petere, "to seek") is a force that makes a body follow a curved path. (not sure but hope this helps )