kinetic energy
Physics
(noun)
The energy associated with a moving particle or object having a certain mass.
Chemistry
Examples of kinetic energy in the following topics:
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Rotational Kinetic Energy: Work, Energy, and Power
- The rotational kinetic energy is the kinetic energy due to the rotation of an object and is part of its total kinetic energy.
- Rotational kinetic energy is the kinetic energy due to the rotation of an object and is part of its total kinetic energy .
- Therefore, it has a rotational kinetic energy of 2.138×1029 J.
- The earth's rotation is a prominent example of rotational kinetic energy.
- Express the rotational kinetic energy as a function of the angular velocity and the moment of inertia, and relate it to the total kinetic energy
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Relativistic Kinetic Energy
- The classical kinetic energy of an object is related to its momentum by the equation:
- Since the kinetic energy of an object is related to its momentum, we intuitively know that the relativistic expression for kinetic energy will also be different from its classical counterpart.
- Indeed, the relativistic expression for kinetic energy is:
- At a low speed ($v << c$), the relativistic kinetic energy may be approximated well by the classical kinetic energy.
- Thus, the total energy can be partitioned into the energy of the rest mass plus the traditional classical kinetic energy at low speeds.
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Kinetic Energy and Work-Energy Theorem
- The work-energy theorem states that the work done by all forces acting on a particle equals the change in the particle's kinetic energy.
- The principle of work and kinetic energy (also known as the work-energy theorem) states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle.
- This definition can be extended to rigid bodies by defining the work of the torque and rotational kinetic energy.
- The work W done by the net force on a particle equals the change in the particle's kinetic energy KE:
- The kinetic energy of the block increases as a result by the amount of work.
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Types of Energy
- The various types of energy include kinetic, potential, and chemical energy.
- Energy associated with objects in motion is called kinetic energy.
- The jet engines are converting potential energy in fuel to the kinetic energy of movement.
- Objects transfer their energy between potential and kinetic states.
- This energy is transformed into kinetic energy that allows a car to race on a racetrack.
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Conservation of Energy in Rotational Motion
- This work went into heat, light, sound, vibration, and considerable rotational kinetic energy.
- Just as in translational motion (where kinetic energy equals 1/2mv2 where m is mass and v is velocity), energy is conserved in rotational motion.
- The final rotational kinetic energy equals the work done by the torque:
- This confirms that the work done went into rotational kinetic energy.
- The motor works in spinning the grindstone, giving it rotational kinetic energy.
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Internal Energy of an Ideal Gas
- Internal energy is the total energy contained by a thermodynamic system, and has two major components: kinetic energy and potential energy.
- Internal energy has two major components: kinetic energy and potential energy.
- Therefore, we will disregard potential energy and only focus on the kinetic energy contribution to the internal energy.
- In this case, the kinetic energy consists only of the translational energy of the individual atoms.
- The average kinetic energy (KE) of a particle in an ideal gas is given as:
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Overview of Temperature and Kinetic Theory
- Also, the temperature of an ideal monatomic gas is a measure of the average kinetic energy of its atoms, as illustrated in .
- The kinetic theory of gases uses the model of the ideal gas to relate temperature to the average translational kinetic energy of the molecules in a container of gas in thermodynamic equilibrium .
- Classical mechanics defines the translational kinetic energy of a gas molecule as follows:
- The distribution of the speeds (which determine the translational kinetic energies) of the particles in a classical ideal gas is called the Maxwell-Boltzmann distribution.
- In kinetic theory, the temperature of a classical ideal gas is related to its average kinetic energy per degree of freedom Ek via the equation:
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Internal Energy
- The internal energy of a system is the sum of all kinetic and potential energy in a system.
- Internal energy has two components: kinetic energy and potential energy.
- The kinetic energy consists of all the energy involving the motions of the particles constituting the system, including translation, vibration, and rotation.
- The kinetic energy portion of internal energy gives rise to the temperature of the system.
- Express the internal energy in terms of kinetic and potential energy
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Problem Solving With the Conservation of Energy
- When they start rising, the kinetic energy begins to be converted to gravitational potential energy ($PE_g$).
- The sum of kinetic and potential energy in the system should remain constant, if losses to friction are ignored .
- The cars of a roller coaster reach their maximum kinetic energy when at the bottom of their path.
- When they start rising, the kinetic energy begins to be converted to gravitational potential energy.
- The sum of kinetic and potential energy in the system remains constant, ignoring losses to friction.
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Kinetic Molecular Theory and Gas Laws
- The collisions exhibited by gas particles are completely elastic; when two molecules collide, total kinetic energy is conserved.
- The average kinetic energy of gas molecules is directly proportional to absolute temperature only; this implies that all molecular motion ceases if the temperature is reduced to absolute zero.
- According to Kinetic Molecular Theory, an increase in temperature will increase the average kinetic energy of the molecules.
- Increasing the kinetic energy of the particles will increase the pressure of the gas.
- Reviews kinetic energy and phases of matter, and explains the kinetic-molecular theory of gases.