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Mechanical Energy (E260 L09), image, image - Coggle Diagram
Mechanical Energy (E260 L09)
Principle of Conservation of Energy
Energy cannot be created or destroyed, it can converted from one form to another, but the total amount of energy within the system never changes (remains unchanged).
Mechanical Energy = Potential Energy (PE) + Kinetic Energy (KE)
Total Energy in the beginning = Total Energy in the end (KE1 + PE1 = KE2 + PE2)
When friction is present, work done by the frictional force is transferred to thermal energy and probably sound and radiant (light) energy
A conservation law (or conservative law) is a physical principle that identifies some quantity that does not change with time
S.I unit for Mechanical Energy: Joule [J]
Important Formulas
Kinetic Energy (KE) = 1/2 mv2
Gravitational Potential Energy (GPE) = mgh
Elastic Potential Energy (EPE) = 1/2 kx2 (1/2 k (delta x)2
Spring Force (F) = kx (k delta x)
Spring Force Equivalent
For n springs in series:
For n springs in parallel:
Forms of Energy
Kinetic Energy (KE)
Scalar Quantity
Can be positive or zero only, but a change in KE can be negative
The energy of a moving object because of its motion, kinetic energy of a moving object depends on the object's mass and speed.
Gravitational Potential Energy (GPE)
Energy of an object due to its position above Earth's surface.
Compared to a Reference Point (base level)
Elastic Potential Energy (EPE)
Energy stored as a result of applying a force to deform an elastic object.
Examples: Springs and Rubber Bands store elastic potential energy that can be transformed into kinetic energy.
Other Forms of Energy
Chemical Energy
Energy is being stored in the bonds of atoms and molecules.
Examples: Batteries, Biomass, Petroleum, Natural gas, Coal
Electrical Energy
Electricity being delivered by tiny charged particles called electrons, typically through a wire.
Example of electrical energy: Lightning (in nature)
Example of electricity-storing device: Capacitor
Nuclear Energy
Energy stored in the particle inside an atomic nucleus
Large amounts of energy can be released when the nuclei are combined or split apart.
Symbol for Potential Energy: U or V, or PE
