Unit 4 Mechanical Systems Topic 3 Energy, Friction, Efficiency Remember to name and date your notes!

Kinetic energy – energy present in moving objects. Potential energy – stored energy Potential Energy is energy that is stored in something and is “potentially available.” There are many forms of potential energy.

Some forms of energy: Thermal energy (heat) is the total energy of all the moving particles in a material or object. Chemical energy is the energy stored in foods and fuels. Mechanical energy is the energy associated with machines

Some Other Forms of Energy Solar Energy Sound Energy Tidal Energy Gravitational Energy Light Energy Wind Energy

An energy converter is any device that can convert energy from one form to another. An energy transmitter, energy is transmitted from one place to another, but no energy is converted.

The school bell converts chemical energy to mechanical energy to sound energy.

The mechanical mouse converts chemical energy (from our bodies) to mechanical energy.

What conversion happens in a solar heater? A solar heater converts light energy into heat energy. (Or light into electrical)

What energy conversion takes place in a toy rocket? The rocket changes chemical energy to mechanical energy, heat energy, light energy and sound energy.

The efficiency of a machine tells you how much of the energy you gave to the machine was transferred to the load by the machine. Efficiency = output energy input energy

Every time a machine does work, some energy is lost due to friction. (Ie. Blades on scissors rubbing together.) Make machines more efficient by reducing friction – adding lubricant such as oil or grease.