Unit 3 - Work & Energy Flashcards
(34 cards)
Energy
The ability to do work
Work
The process of transferring energy
Translational Kinetic Energy (Kinetic)
The energy possessed by an object when it is moving in a linear fashion (the whole object is moving in a straight line).
Gravitational Potential Energy (Potential)
The energy available due to the relative position of 2 objects with mass. As you raise an object (changing its position relative to the center of the earth) it has more gravitational potential energy.
Elastic (spring) Potential Energy
The energy stored in the stretched or compressed chemical bonds of a material which has been deformed (a macroscopic object like this must have many, many particles who’s relative positions are being altered).
Power
The rate at which work is done, or the rate at which energy is transferred.
Efficiency
Efficiency of a process is the percent of the input energy that is available as useful output energy.
Work-energy theorem
The work-energy theorem tells us that the work done on an object is equal to the change in the object’s energy.
The law of conservation energy
Energy is neither created of destroyed, it is only transformed from one form to another and transferred from one object to another.
Isolated system
- Energy isn’t created of destroyed
- Energy isn’t transferred in or out of the system (No work is done on the system)
- Mass doesn’t enter or leave the system
Closed system
- Energy isn’t created or destroyed
- Energy can be transferred in out out of the system (work is done on system)
- Mass doesn’t enter or leave the system
Internal energy
The sum of the thermal energy and bond energy
Thermal energy
The molecular kinetic energy associated with the random vibrational, rotational and translational motion of the particles
Bond energy
The potential energy (electrical in nature) in the intermolecular and intramolecular bonds within the substance.
Temperature
A measure of the average internal kinetic energy (the thermal energy) of the particles in a substance)
Heat
The transfer of energy between objects (or systems) due to a temperature difference between the objects; heat is a process of transferring energy!
Mass defect
The difference between the mass of the atom and the sum of the mass of the individual parts
Binding energy
The amount of energy that must be added to allow the nucleons to separate (EB *B is a subscript). To calculate it, we need to find the energy equivalent of the mass defect for the atom.
Binding energy per nucleon
Comparing different elements, look at amount of energy that is needed on average to remove one nucleon from any given atom, EB/A
Radioactivity
The spontaneous disintegration of atomic nuclei through the emission of radiation or particles.
Transmutation
Particle emitted from nucleus, changing and resulting nucleus of new element which is more stable.
Alpha decay
A nucleus emits an alpha particle which consists of 2 protons and 2 neutrons
Beta-minus decay (beta decay)
Neutron becomes proton and an electron is ejected from the atom. It can occur whenever the mass of the original neutral atom is larger than the final neutral atom.
Neutrino
Neutrinos have no charge and negligible mass
