Physics key concept

describe matter using the kinetic particle model

the kinetic particle model describes matter as consisting of particles in constant motion, except at absolute zero

do all substances have internal energy

all substances have internal energy due to the motion and separation of their particles

temperature

temperature is the measure of the average kinetic energy of particles in a system

how does thermal equilibrium occur

two systems in contact transfer energy between particles so that eventually the systems reach the same temperature; they are in thermal equilibrium

capacity to do work

a system with thermal energy has the capacity to do mechanical work; when work is done, the internal energy of the system changes

mechanical work

to apply force over a distance

change in internal energy of a system =?

because energy is conserved, the change in internal energy of a system is equal to the energy added by

heating, or removed by cooling, plus work done on/by the system

efficiency formula:

efficiency = energy output / energy input * 100%

forms of heat transfer

heat transfer occurs between and within systems via conduction, convection, and/or radiation