Sit wherever you like. Temporarily. Thursday – note check on solar system Remember, your notes need to be in a folder and in order. Do this by Thursday. Some of you are still missing assignments (e.g. Bernoulli’s principle essay from forever ago). Turn it in. Assignment before we start: Read 13.1 pg 442- 446. If you finish before we begin, continue reading something else or doing something productive for yourself. You’re going to spend a lot of time with yourself, make sure you’re entertaining.

Chapter 13, Section 1 (We are only doing section 1 and 2 from this chapter): What is energy? Key concepts: How are energy, work, and power related? What are the two basic kinds of energy? Key terms: energy, kinetic energy, potential energy, gravitational potential energy, elastic potential energy

Yeeaaah it’s almost May Yeeaaah it’s almost May! Let’s do this science stuff and learn; I know you want to! (you’re all much cuter than this guy)

Energy In physics, the ability to cause change (or do work) is called energy. Energy is measured in joules (j) Something possesses energy if it has the ability to cause change (or do work) Energy exists in many forms, but it is always either kinetic or potential. (more on this in a sec)

Energy, Work, and Power Work and energy: Work is the transfer of energy, and is measured in joules. Power and energy: if the transfer of energy is work, then power is the rate at which energy is transferred, or the amount of energy transferred in a unit of time. Power= (energy transferred/time)

Two basic kinds of energy: potential and kinetic

Kinetic Energy – ENERGY OF MOTION!! Two basic kinds of energy are kinetic energy and potential energy. Whether it is kinetic or potential depends on if it is moving or not. Kinetic energy – when an object is in motion it has KINETIC energy Things that affect it: Mass – kinetic energy increases as mass increases; bigger things have more kinetic energy Velocity – kinetic energy increases as velocity increases; faster things have more kinetic energy Changing the velocity will have more of an effect than changing mass by the same factor

Calculating Kinetic Energy Kinetic energy = ½ x mass x velocity2 Ew, equations.

Potential energy = stored energy! Stored energy that results from the position or shape of an object is called its potential energy. It has the potential to do work. (meaning, it is currently NOT doing work, but it COULD at any time) Potential energy related to an object’s height is called gravitational potential energy. The gravitational potential energy of an object is equal to the work done to lift it. Gravitational potential energy = weight x height

Example: If a ski jump is 40 meters high, and a skier weighs 500 newtons, then the skier has 500 newtons x 40 meters, or 20,000 J, or gravitational potential energy Because gravitational potential energy = weight x height

Elastic potential energy An object gains a different type of potential energy when it is stretched. The potential energy associated with objects that can be stretched or compressed is called elastic potential energy. For example: When an archer pulls back an arrow, the bow changes shape. The bow now has potential energy.

Yay! You’re learning about energy! Please complete pg 446 1abc, 2abc, 3 and 4 Write 1 example (not in the book or my notes) of an example where stored (potential) energy becomes kinetic (moving energy). BTW, saying “I couldn’t think of any” is not acceptable. THINK. USE THE INTERNET. EMAIL ME FOR HELP. You have resources. All due tomorrow at beginning of class. You can do both in your notes. In 10-15 minutes we will begin a Bill Nye video on Energy (which you need to watch – not work on other stuff, not talk, not pass notes, not sleep, etc. You need to WATCH it because yay you might learn stuff yay!) https://www.youtube.com/watch?v=btLU2lb3-xs