Chapter 7 Flashcards
Total energy conversion rate of a person at rest
Basal metabolic rate
Energy in a substance stored in the bonds between atoms and molecules that can be released in a chemical reaction
Chemical energy
Rule that the sum of the kinetic energies and potential energies remains constant if only conservative forces act on and within a system
Conservation of mechanical energy
Force that does the same work for any given initial and final configuration, regardless of the path followed
Conservative force
Measure of the effectiveness of the input of energy to do work; useful energy or work divided by the total input of energy
Efficiency
Energy carried by a flow of change
Electrical energy
Ability to do work
Energy
Oil, natural gas, and coal
Fossil fuels
Force between surfaces that opposes one sliding on the other; friction changes mechanical energy into thermal energy
Friction
Energy an object has due to its position in a gravitational field
Gravitational potential energy
Older non-SI unit of power, with 1 HP = 746 W
Horsepower
SI unit of work and energy, equal to one newton-meter
Joule
Unit used primarily for electrical energy provided by electric utility companies
Kilowatt-hour
Energy an object has by reason of its motion, equal to 1/2 mv² for the translational (i.e., non-rotational) motion of an object of mass m moving at speed v
Kinetic energy
General law that total energy is constant in any process; energy may change in form or be transferred from one system to another, but the total remains the same
Law of conservation of energy
Sum of kinetic energy and potential energy
Mechanical energy
Rate at which the body uses food energy to sustain life and to do different activities
Metabolic rate
Work done by the net force, or vector sum of all the forces, acting on an object
Net work
Force whose work depends on the path followed between the given initial and final configurations
Nonconservative force
Energy released by changes within atomic nuclei, such as the fusion of two light nuclei or the fission of a heavy nucleus
Nuclear energy
Energy due to position, shape, or configuration
Potential energy
Stored energy of a spring as a function of its displacement; when Hooke’s law applies, it is given by the expression 1/2 kx² when x is the distance the spring is compressed or extended and k is the spring constant
Potential energy of a spring
Rate at which work is done
Power
Energy carried by electromagnetic waves
Radiant energy
Sources that cannot be used up, such as water, wind, solar, and biomass
Renewable forms of energy
Energy within an object due to the random motion of its atoms and molecules that accounts for the object’s temperature
Thermal energy
Work done on an external system
Useful work
SI unit of power, with 1 W = 1 J/s
Watt
Transfer of energy by a force that causes an object to be displaced; the product of the component of the force in the direction of the displacement and the magnitude of the displacement
Work
The result, based on newton’s laws, that the net work done on an object is equal to its change in kinetic energy
Work-energy theorem
