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Chapter 6: Work and Energy - Coggle Diagram
Chapter 6: Work and Energy
Law of Conservation of Energy:
the total energy of the universe is unchanged by any physical process
Total energy before = Total energy after
Work:
energy transferred to or from an object by means of a force acting on the object
scalar product of two vectors: displacement and force
the product of the net component of the force in the direction of the displacement and the magnitude of the displacement
can be positive, negative, or zero
Gravitational Potential Energy
the gravitational potential energy (Pe) is the energy that an object of mass
m
has by virtue of its position relative to the surface of the earth. that position is measured by the height
h
of the object relative to an
arbitrary zero
level
Work-energy theorem
when work is done on an object causing exclusively a change in its speed, that work is equal to the change in kinetic energy of the object
Conservative Force
a force is conservative when the work it does on a moving object is independent of the path between the object's initial and final positions
Examples:
gravity
spring force
electrostatic force
Mechanical Energy
the sum of the kinetic and potential energies
E = K + U
Elastic potential Energy
work done by an ideal spring depends on initial and final positions of the moveable end, but not on the path that was taken
the change in elastic potential energy is the negative of the work done by the spring
Power
the average power is the amount of energy transferred divided by the time the transfer takes
SI units: Watts (W)
rate at which work is done