24 Main Ideas
Week 6
Work and Energy
Concept Map of the Week
Note: image by Chudaeva, E. (2022).
Concept Trailer
Gravitational Potential and Kinetic Energy
Watch this video.
Then watch the video again and answer the following questions:
- How gravitational potential energy is defined/
- How kinetic energy is defined?
- What is mechanical energy?
- What happens with mechanical energy of the roller coaster cars during motion?
- Can we say that mechanical energy is conserved when the train moves down the slope? Explain.
- What other types of energy are present during roller coaster ride?
Key Terms
Review the following key terms (glossary chapter 7):
chemical energy
the energy in a substance stored in the bonds between atoms and molecules that can be released in a chemical reaction
conservation of mechanical energy
the rule that the sum of the kinetic energies and potential energies remains constant if only conservative forces act on and within a system
conservative force
a force that does the same work for any given initial and final configuration, regardless of the path followed
efficiency
a measure of the effectiveness of the input of energy to do work; useful energy or work divided by the total input of energy
energy
the ability to do work
gravitational potential energy
the energy an object has due to its position in a gravitational field
joule
SI unit of work and energy, equal to one newton-meter
kinetic energy
the energy an object has by reason of its motion
law of conservation of energy
the 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
mechanical energy
the sum of kinetic energy and potential energy
metabolic rate
the rate at which the body uses food energy to sustain life and to do different activities
net work
work done by the net force, or vector sum of all the forces, acting on an object
potential energy
energy due to position, shape, or configuration
power
the rate at which work is done
useful work
work done on an external system
watt
(W) SI unit of power, with 1 W=1 J/s
work
the 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-energy theorem
the result, based on Newton’s laws, that the net work done on an object is equal to its change in kinetic energy
More terms can be found in the textbook Glossary.
