2 LOL ChartsThere will be an L at each time you want to show how the energy in the system is distributed.Between each L, the O shows energy entering or leaving the system.Energy commonly leaves a system in the form of heat and sound.
3 Common Types of EnergyEg is gravitational potential energy. It is proportional an object’s height above the earth’s surface.Ek is kinetic energy. It is the energy of motion.Eel is elastic energy. It is the energy stored in a spring or other stretchy object.Eth is thermal energy. It is proportional to temperature.Ech is chemical energy. This is stored in chemical bonds. We rarely use this in physics.
4 Pie Charts The size of the slices shows how the energy is distributed. When energy leaves the system, we show the amount that left as Es
5 Work and EnergyW = F ∆x Work is force multiplied by change in position. Unit: Joules (J) = Newtons x meters (Nm) When a system does work, it gives energy to something else. When work is done on a system, it receives energy. The amount of work done is also the area underneath an F vs ∆x graph
6 Gravitational Energy Fg is basically constant. If I lift up an object to a height h, I do work on it and give it energyW = Eg = Fg ∆xEg = mgh
7 Spring EnergyIn our lab, we found that a spring force is proportional the change in its length from equilibrium (Hooke’s Law)The area under its F vx ∆xgraph is the area of a triangle.Specifically, Eel=1/2 k (∆x)2
8 Kinetic EnergyEk=1/2 m (v)2 As you can see, Ek is directly proportional to mass and to velocity squared.
9 Conservation of Energy Energy is never created or destroyed, but it does change formsThe initial energy of a system plus any energy added to the system is equal to the final energy of the system plus the energy that leaves the system.E0 + Einput = Ef + Edissipated
10 PowerPower is the rate at which energy is used.P= ∆𝐸 ∆𝑡