4.4 What is Energy?

Unit 7: Power & Energy
Lesson 4: What is Energy

Vocabulary

• chemical energy – a form of energy that is stored in the bonds between atoms in a compound

•  elastic potential energy – energy that is stored when an elastic object is stretched or compressed

•  gravitational potential energy – a form of potential energy that is stored in an object

•  kinetic energy – energy according to its location in a gravitational field in motion

•  potential energy – energy an object has due to its position, condition, or shape

Energy & Work Teamwork

Remember: Energy is defined as the ability to do work and work describes the force that is exerted on an object in order to cause it to move and the force must be applied in the same direction that the object moves

→ ENERGY IS THE ABILITY TO EXERT A FORCE ON AN OBJECT TO CAUSE IT TO MOVE ← 

Two types of Energy: kinetic and potential

Kinetic Energy: energy in motion

• Energy in motion – the result of doing work

• Si unit is Joule (J)

  • Standard unit for energy & work

  • Other units: (N•m) and (kg•m2/s2)

• KE is associated with an object in motion, this form of energy is dependent on both the mass and velocity of an object

Kinetic Energy

Potential Energy: energy stored

• ENERGY AN OBJECT HAS DUE TO ITS POSITION, CONDITION, OR SHAPE

• ELASTIC PE: energy that is stored when an elastic object is stretched or compressed (rubber band, bow & arrow, etc)

• CHEMICAL PE: energy stored in the bonds of atoms and molecules of compounds/ when a compound undergoes chemical reaction, energy is released

• GRAVITATIONAL PE: Earth has natural gravitational attraction for object that results in a type of stored energy / energy is stored in an object due its vertical position or height

  1. Because GPE comes from force of gravity, this energy form is dependent on both the height and mass of an object

  
  

Potential Energy

Poll

You going to the game tonight?

• YES, wouldn't miss it!

• I wish!

• No, I can't make it