1.ENERGY


Is the capacity of a body to perform transformation and do work.Food labels provide us information abaut the nutrional qualities of the food we eat.Our bodies are like machines that transform the energy in food into metabolic (chamical) energy and muscular (mechanical) energy.
Muscular energy was the only source of energy that people had.
Technological objects that we use also require energy to function correctly and perform tasks.


1.1 FORMS OF ENERGY:

• Potential:Associated with the heigh of an object above the ground,or the storage of energy in a spring.
• Kinetic:The energy of physical movement.
• Mechanical:The sum of potential and kinetic energy.
• Sound:The energy of sound waves,which are produced by vibrations and propagated though a physical médium.
• Electrical:The product of an electrical current.
• Nuclear:The energy in the nucleus of an atom.
• Luminous:Associated with light.
• Thermal or Calorific:Associated with the movement of particles in matter.
• Chemical:Results from the formation or descomposition of substances.
• Electromagnetic:Occurs when electrical currents créate magnetic fields.

1.2 UNITS OF MEASUREMENT FOR ENERGY:


Energy is measured in "joules".When energy takes the form of heat,we often express it as "calories".

1.3 POWER:

Power is a measurement of how quickly work is done.The power of a machine is the amount of work that it can do in a certain amount of time.