5.1 The Nature of Energy
Energy: the capacity to do work or to transfer heat
Work: energy used to cause an object with mass to move
Heat: the energy used to cause the temperature of an object to increase -the energy transferred between a system and its surroundings as a result of their difference in temperature

Force: any kind of push or pull extorted on an object (example: gravity)
Kinetic Energy and Potential Energy
Kinetic Energy
-objects can possess kinetic energy if they have mass and are in motion -to find the magnitude of kinetic energy= - Ek= (1/2)mv^2 -Ek= magnitude of kinetic energy -m= mass -v= speed
-kinetic energy increases as speed of object increase
-kinetic energy increases with increasing mass
Potential Energy Object can potential energy ( another form of energy) -depends on position relative to other objects -potential energy arises when there is force operating on an object -biker example -bicycle possesses certain potential energy by virtue of their elevation -energy decreases as move downward -lost energy= other forms of energy (ex. Kinetic energy) -potential energy equation: -Ep=mgh -m – mass -h: height -g: gravitational constant -electrostatic potential energy -energy arised from interactions between charged particles -electrostatic potential energy: proportional to electrical charges on the two objects and inversely proportional to distance separating them -equation: -Eel: (kQ1Q2)/d -k: constant of proportionality -8.99x10^9 J-m/C^2 -C is coulomb (electrical charges) -J is Joule, unit of energy -Q1 and Q2: electrical charges -on the order of