Total Mechanical Energy
Total Mechanical Energy - Related Videos
01:05
Conservation of Mechanical Energy
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2023
The mechanical energy E of a system is the sum of its potential energy U and the kinetic energy K of the objects within it. What happens to this mechanical energy when only conservative forces cause energy transfers within the system—that is, when frictional and drag forces do not act on the objects in the system? Also assume that the system is isolated from its environment; in other words no external force from an object outside the system causes energy changes inside the system. When a...
04:10
What is Energy?
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2020
The universe is composed of matter in different forms, and all forms of matter contain energy. The different forms of energy on Earth originate from the Sun — the ultimate energy source. Plants capture light energy from the Sun, and, via the process of photosynthesis, convert it into chemical energy. This stored energy from plants can be harnessed in many ways. For example, eating plant products as food provides energy for our body to function, and burning wood or coal (fossilized plants)...
08:52
Energy and Work
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2023
Source: Ketron Mitchell-Wynne, PhD, Asantha Cooray, PhD, Department of Physics & Astronomy, School of Physical Sciences, University of California, Irvine, CA This experiment demonstrates the work-energy principle. Energy is one of the most important concepts in science and is not simple to define. This experiment will deal with two different kinds of energy: gravitational potential energy and translational kinetic energy. Gravitational potential energy is defined as the energy an object...
02:39
Gibbs Free Energy
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2020
One of the challenges of using the second law of thermodynamics to determine if a process is spontaneous is that it requires measurements of the entropy change for the system and the entropy change for the surroundings. An alternative approach involving a new thermodynamic property defined in terms of system properties only was introduced in the late nineteenth century by American mathematician Josiah Willard Gibbs. This new property is called the Gibbs free energy (G) (or simply the free...
01:21
Free Energy
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2019
Free energy—abbreviated as G for the scientist Gibbs who discovered it—is a measurement of useful energy that can be extracted from a reaction to do work. It is the energy in a chemical reaction that is available after entropy is accounted for. Reactions that take in energy are considered endergonic and reactions that release energy are exergonic. Plants carry out endergonic reactions by taking in sunlight and carbon dioxide to produce glucose and oxygen. Animals, in turn, break down the...
FAQs
Conservative forces transfer energy between kinetic and potential forms without changing their combined amount. For example, gravity can exchange an object's motion energy with energy associated with position, while a spring can exchange motion energy with energy stored through configuration. This accounting allows the system's motion to be analyzed through energy changes rather than by tracking every force effect separately.
Friction is nonconservative, so it reduces the amount of energy remaining in mechanical form. The lost mechanical energy is transformed into thermal or other forms rather than simply disappearing. Consequently, a calculation that assumes constant mechanical energy may not predict the motion accurately when friction or another nonconservative force has a significant effect.
An energy balance connects an object's kinetic contribution with its potential contribution at different positions or configurations. Where potential energy changes, the available kinetic energy and therefore the speed change accordingly. The same balance helps locate turning points, where the motion changes, and supports analysis of equilibrium behavior without requiring a complete solution for the motion.
First identify the kinetic and potential energy contributions relevant to the system. Next determine whether the important forces are conservative or whether friction and other nonconservative effects must be included. Then compare the energy amounts between the states of interest. This procedure can predict speed, turning points, or energy changes directly from the system's energy accounting.
The method is useful when motion involves gravity, springs, or other conservative forces that exchange kinetic and potential energy. It provides a practical route for studying falling objects, pendulums, spring systems, and planetary orbits. In each case, energy comparisons can reveal how motion changes across positions or configurations without solving every detail of the trajectory.
The same framework links apparently different systems by focusing on conversion between motion energy and stored energy. Gravity dominates the analysis of falling objects and orbital motion, while spring forces govern configuration-dependent exchanges in spring systems. Pendulums similarly illustrate changing energy contributions as their motion evolves, making the approach relevant across several areas of physics.