Forms and Transformations ENERGY Forms and Transformations

What is energy? Energy is the ability to do work or cause change. It can change the temperature, shape, speed, or direction of an object.

What are the two basic kinds of energy? Potential energy is stored energy. Kinetic energy is energy in motion. Kinetic energy increases when the mass or velocity of the object increases. Mechanical energy is associated with the position and motion of an object. M.E. is a combination of an object’s potential energy and kinetic energy.

What are some additional forms of energy? Gravitational P.E. – depends on the height of an object Elastic P.E. – stored in stretched or compressed objects Chemical P.E. – stored in chemical bonds between atoms and molecules; released through chemical reaction Nuclear P.E. – stored in the nucleus of atoms; released through fission or fusion

More forms of energy… Electromagnetic K.E. – energy of light and other forms of radiation; travels in waves Thermal (P.E. and K.E.) – total P.E. and K.E. of the molecules in an object. KE increases with temperature Electrical (P.E. or K.E.) – energy of electric charges, stored or in motion.

What is an object’s mechanical energy? Mechanical energy is associated with the position and motion of an object. M.E. is a combination of an object’s potential energy and kinetic energy.

KINETIC ENERGY The energy an object has due to its motion is kinetic energy. Kinetic energy depends on the object’s mass and velocity K.E. = (½ x Mass) x (Velocity2) Measured in Joules

POTENTIAL ENERGY Stored energy that results from the position or shape of an object is potential energy. Gravitational P.E. increases as weight and height increase. G.P.E. = Weight x Height Measured in Joules

What is the Law of Conservation of Energy? The Law of Conservation of Energy states that energy cannot be created or destroyed. When one form of energy is transformed to another, the total amount of energy is the same before and after the process.

How are different forms of energy related? Most forms of energy can be changed into other forms. This change is called an energy transformation. - (A toaster transforms electrical energy to thermal energy) One of the most common transformations is between potential and kinetic energy. - (A stretched rubber band (E.P.E.) is let go (K.E.))

Energy transformation examples… Spinning top Mechanical energy changes to thermal energy because of friction. Ball on stairs - Gravitational P.E. changes to kinetic energy once the ball starts rolling.

How are energy, work, and power related? Work is done when a force moves an object through a distance. When one object does work on another object, some energy is transferred. This transfer is work. Power is the rate at which energy is transferred (amount of energy per unit of time).