Energy stores, work and power - Intro

Every push, fall and stretch in physics can be told twice. Once as forces, and once as energy. The forces chapters told it the first way. This chapter tells the same events the second way: where the energy sits, where it moves when something changes, and how fast. Exam questions on energy come in two kinds. Some want a change described in words. Others want a number, in joules.

Every video here is for everyone, Foundation and Higher, combined science and separate physics alike. Nobody skips anything in this chapter.

If energy is new to you, start with Energy stores and the three ways a system's energy changes. Everything after it stands on that video. It covers the word answers, the part of this chapter where slips are recorded most often. Energy transfer diagrams and the common scale follows straight on. It shows the whole system in one picture, before the change and after it. If the words are already secure and it is the numbers that worry you, begin at Work done and energy transfer. It turns a push into joules. Then comes Power as the rate of energy transfer. It keeps apart how much energy moves and how fast it moves, two ideas nearly half of the students on one paper mixed up. If your exam is close and you want the equations, go to Kinetic energy, Gravitational potential energy and Elastic potential energy. On every board, you learn the first two of those by heart. The elastic one is printed for you on the equation sheet. The kinetic and elastic equations both square something, and slipping on that step is common, so each of those videos gives it a line of its own. Each video can be searched by its name or by its code. The scholafly.com website is the quickest way in, because it indexes every video in every subject.

Next in the chapter is Energy stores and the three ways a system's energy changes. Hopefully that's next in your feed, but if not, search for ScholaFly P H oh five, oh one.

Every other video is on scholafly.com too, easy to search by video code or by keyword. Whatever you're revising, go there and have a look, or, watch the next video.