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CHAPTER 7: CONSERVAION OF ENERGY - Coggle Diagram
CHAPTER 7: CONSERVAION OF ENERGY
The Law of Conservation of Energy
Energy cannot be created nor destroyed. Energy can be transformed from one form to another but the otal amount of energy never changes.
Does not conserve mechanical energy.
Conservative and Non-Conservative Forces
Conservative Force
A force is conservative when the net work done by the force on an object mving around any closed path is ZERO.
Work Done by the force from one point to another only on the initial and final position of the object.
Example: Gravitational Energy, Potential Energy, Elastic Energy,
Electrical Energy.
Non- Conservative Force
Example: Friction, Air Resistance, Tension in a cord, Push or pull by a person, motor or rocket propulsion.
When friction is present, thw work depends on the starting point, path taken and ending point.
Gravitational Poitential Energy and Escape Velocity
Gravitational Potential Energy
Energy stored in an object due to its position above the Earth's surface.
E=mgh
Gravitational Force:
Work Done on object moving in Earth's Gravitational Field:
Escape Velocity
Objects that escape from the gravitational field of the massive body without further impulse.
Potential Energy
Energy stored in an object due to its position.
dependant on height.
P.E. =mgh
Examples: a stretched elastic band, an object at a height above the ground, a wound-up spring.
Potential Energy can be Kinetic Energy when dropped.
For One dimension:
For Three Dimension:
Mechanical Energy and Its Conservation
Total Mechanical Energy definition:
Conservation of Mechanical Energy:
Principle of Mechanical Energy: if conservative forces are doing work, the total mechanical energy of a system does not increase nor decrease. It stays constant as it is conserved.
Power
Rate at which work is done.
S.I. Unit: Watt (W)
Average Power:
Instantaneous Power:
Also defined as rate at which energy is transferred.
