Please enable JavaScript.
Coggle requires JavaScript to display documents.
Energy, Work and Power - Coggle Diagram
Energy, Work and Power
Work
Definition
The
product
of a
force
on a body and the
displacement
of the body
in the direction of the force
.
Formula
Fig 12 of
https://tinyurl.com/PhysicsIP3
Quantity
Scalar Quantity
SI Unit: Joule (J)
Work-Energy Theorem (WET)
Formula
Fig 13 of
https://tinyurl.com/PhysicsIP3
Definition
The
net work done
by
external forces
acting on a body is
equal
to the change in kinetic energy of the body.
Graphs
Force/Displacement graphs:
Area under F/s graphs = Work Done
by F
Force/Extension or Force/Compression (of spring) graphs:
Area (triangle) under graph = Work Done
Energy
Quantity
SI Unit: Joule (J)
Scalar Quantity
Forms
Chemical Potential Energy
Energy stored in substances due to positions of particles making up the substances.
Nuclear Energy
Energy released during nuclear fission/fusion
Elastic Potential Energy
Formula: Fig 11 of
https://tinyurl.com/PhysicsIP3
Energy stored in a spring when it is stretched/compressed
Internal Energy
Sum of microscopic kinetic and potential energies of all atoms and molecules in a body
Gravitational Potential Energy
Formula: Fig 10 of
https://tinyurl.com/PhysicsIP3
Energy a body has due to its position above a reference level (where GPE = 0J)
Kinetic Energy
Formula: Fig 9 of
https://tinyurl.com/PhysicsIP3
Energy a body has due to its movement
Principle of Conservation of Energy (COE)
Definition
The COE says that
Energy cannot be created or destroyed
, but can be
converted
from one form to another. The
total energy of an isolated system remains constant
.
Applications (Used for solving problems)
Loss in GPE = Gain in KE
, assuming
no loss of energy to other forms
besides conversion between GPE and KE.
Total Energy at A = Total Energy at B
(from second line of COE). This is when work done by
other resistive forces are put into consideration
.
Power
Definition
The
rate
of
energy transfer
Formula
Fig 14 and 15 of
https://tinyurl.com/PhysicsIP3
Quantity
SI Unit: Watt (W)
Scalar Quantity
The kilowatt-hour
Fig 16 of
https://tinyurl.com/PhysicsIP3
The amount of
energy
supplied by
1 kilowatt of power for 1 hour.
Efficiency
A measure of how
well
a system
turns input energy to useful work
.
Formula: Fig 17 of
https://tinyurl.com/PhysicsIP3
Scalar
Quantity,
NO UNITS