Transcript Energy

Energy
Energy & Work
• Closely related
• Energy: ability to do work
• Work: transfer of energy
• Both measured in Joules
Energy Types
1. Kinetic Energy: Energy in motion
2. Potential Energy: Stored energy
(not moving)
•
depends on position or condition of
object
Examples of KE
Examples of PE
Boulder on top of cliff
battery
Firecracker
Calculating KE
KE = ½ mv2
m = mass
v = velocity
• Which increases kinetic energy
more: doubling the mass or doubling
the velocity?
Gravitational PE
• PE that depends on object’s height,
and weight
G.P.E. = mgh
m = mass
g = 9.8 m/s2
h= height.
Which will have greater
GPE: a rock on a 3 story
ledge or a rock on a 20
story ledge?
Mechanical Energy
• PE Converts to KE and vice versa
• Mechanical Energy = KE + PE
– Total energy
• Skier
• Roller Coaster
• Dart
Energy conversions
•Law of conservation of energy:
•Energy cannot be created or
destroyed, only converted from
one form to another