The Nature of Energy

1. The Nature of Energy Section 4.1

2. Energy • Every change that occurs involves . • Moving objects have energy • You can tell an object has energy when it: • Changes its environment • Changes itself • Energy • Electrical – moving electrons • Chemical – from bonds • Thermal- heat

3. Energy • Energy exists in many different forms • It may look different, but it’s still energy. • Examples: fire, movement, gasoline in a bucket • Kinetic energy- energy in the form of motion • Depends on mass and velocity of an object • Increase in either mass or velocity = increase in energy • KE =1/2 mv2 • Units = kg*m/s

4. Types of Energy • KE = ½ mv2 Velocity changes will impact KE more because velocity is squared. • Potential Energy – energy of position • Energy in stationary objects and bonds • Elastic Potential Energy – Energy of compression or stretching • Chemical Potential Energy – Energy stored in bonds • Gasoline, food, hand warmers

5. Types of Energy • Gravitational Potential Energy- Energy stored due to position above the surface of Earth • Depends on mass of object, height of object above ground, and acceleration due to gravity • GPE = m x h x g g = acceleration due to gravity • All energy – measured in units of Joules • 1 J = 1 kgm2/ s2 • Energy can be converted: • As an object falls, GPE decreases and KE increases