Unit 3: Energy

• Energy is the ability to move or cause change in motion.
• Energy is measured in Joules (J) and it is a scalar.
• A system is a set of objects you are analyzing.
• An open system can exchange energy with its surroundings due to external forces.
• A closed system only exchanges energy with the items inside the system (internal forces).
• Mechanical Energy is the sum of potential and kinetic energy.
• Kinetic Energy is the energy of a moving object and is shown by the variable: K.
• Potential Energy is the energy from two objects exerting a force due to their positions (gravitational, elasticity, etc.).
• Thermal Energy is the energy from heat usually from friction.
• Potential Energy requires 2 or more objects.
• Conservation of Energy is where the amount of energy before equals the amount of energy after.
• Energy can't just disappear.
• Work is a change in energy caused by a force acting across a displacement.
• If there is no displacement then there is not net work.
• The work equation is Work = (Force)(Displacement).
• Work is measured in Joules.
• If a force is working against motion, the work is negative.
• The Gravitational Energy Formula is:


  Gravitation Potential Energy = (Force of Gravity)(y-Displacement)
• The Kinetic Energy Formula is K = 1/2mv^2