91 Questions
Which of the following best describes potential energy?
Energy that depends on the configuration of a system
What is the equation for gravitational potential energy?
$U_g = mgy$
What is the work done by an external agent on a system equal to?
The change in potential energy of the system
When is the gravitational potential energy equation valid?
Only for objects near the surface of the Earth
What is the unit of gravitational potential energy?
Joules
What does Equation 7.20 mathematically describe?
The change in potential energy of a system
Which type of energy does the system possess when the spring is relaxed and the block is not moving?
Zero energy
When the spring returns to its original length, what type of energy does the system contain?
Kinetic energy
What type of energy does the bar chart show decreasing when the block is released and moving to the right while still in contact with the spring?
Elastic potential energy
Which type of energy does the system possess when the book is sliding on the surface and slowing down due to friction?
Internal energy
What type of energy does the bar chart show transforming to internal energy as the book slows down due to friction force?
Kinetic energy
What type of energy does the system possess at the instant the book is released by your hand?
Kinetic energy
Which type of energy is the algebraic sum of the kinetic energies of all members of a system?
Kinetic energy
In a system consisting of a book and the Earth interacting via the gravitational force, what happens to the kinetic energy of the system when the book is lifted slowly from rest?
The kinetic energy of the system remains constant
When can the kinetic energy of a stationary object in a system be neglected?
When the object is very massive
Which energy storage form does the energy change of a system appear as when it is not in the form of kinetic energy?
Internal energy
In a system of two electrons, what does the kinetic energy of the system include?
The kinetic energy of both electrons
What is the work-kinetic energy theorem?
The work done on a system is equal to the change in its kinetic energy
Which type of potential energy depends only on the vertical height of an object above the surface of the Earth?
Gravitational potential energy
According to the text, the same amount of work must be done on an object-Earth system whether the object is lifted vertically from the Earth or is pushed up a frictionless incline.
True
What is the equation for the work done on an object by an agent moving the object through a displacement having both vertical and horizontal components?
$W_{ext} = mgy_f - mgy_i$
In the equation for gravitational potential energy, what does $y_i$ represent?
Initial vertical position
What is the equation for the force exerted by a spring on a block in the block-spring system?
$F_s = 2kx$
What is the equation for the elastic potential energy associated with the block-spring system?
$U_s = rac{1}{2}kx^2$
According to the principle of conservation of energy, what is equal to the amount of internal energy in the system after the book has stopped sliding?
The amount of kinetic energy in the system at the initial instant
What does the work done by the gravitational force on an object depend on when it is moving downward near the surface of the Earth?
The object's elevation
What does the energy transformation to internal energy due to friction on an incline depend on?
The object's distance traveled
What is the classification of the gravitational force?
Conservative
What is the classification of the friction force?
Nonconservative
Which one of the following is true about the work done by the gravitational force and the energy transformation due to friction forces?
The work done by the gravitational force depends on the object's elevation, while the energy transformation due to friction forces depends on the object's distance traveled
True or false: Potential energy is a scalar quantity.
True
True or false: The potential energy of a system is determined by the configuration of the system.
True
True or false: The potential energy of a system can only be associated with specific types of forces acting between members of the system.
True
True or false: The work done by an external agent on a system appears as a change in the gravitational potential energy of the system.
True
True or false: The equation for gravitational potential energy is $U_g = mgy$.
True
True or false: The gravitational potential energy of an object near the surface of the Earth is valid only when the vertical displacement of the object is small compared with the Earth's radius.
True
True or false: The kinetic energy of a system consisting of two or more particles is the algebraic sum of the kinetic energies of all members of the system.
True
True or false: The kinetic energy of a system consisting of a ball and the Earth can be considered as just the kinetic energy of the ball.
True
True or false: The kinetic energy of a system of two electrons must include the kinetic energies of both particles.
True
True or false: The work done on a system consisting of a book and the Earth by lifting the book slowly from rest does not cause a change in the kinetic energy of the system.
True
True or false: The work-kinetic energy theorem applies to all forms of energy changes in a system.
False
True or false: The energy change of a system that is not in the form of kinetic energy must appear as some form of energy storage other than kinetic energy.
True
True or false: The kinetic energy of the system is zero after the book has stopped sliding.
True
True or false: The total energy of the system remains constant during the process.
True
True or false: The amount of internal energy in the system after the book has stopped is equal to the amount of kinetic energy in the system at the initial instant.
True
True or false: The work done by the gravitational force on an object does not depend on whether it falls vertically or slides down a sloping incline with friction.
True
True or false: The energy transformation to internal energy due to friction on an incline depends on the distance the object slides.
True
True or false: The gravitational force is classified as conservative and the friction force is classified as nonconservative.
True
True or false: The elastic potential energy of the system decreases when the block is released and moving to the right while still in contact with the spring?
True
True or false: The kinetic energy of the system increases when the block is released and moving to the right while still in contact with the spring?
True
True or false: The total energy of the system remains fixed when the block is released and moving to the right while still in contact with the spring?
True
True or false: The energy bar chart in Figure 7.16a shows that the system contains zero energy because the spring is relaxed and the block is not moving?
True
True or false: The work done on the surface by the sliding book is positive, but there is no increase in the surface's kinetic energy or potential energy?
True
True or false: The energy associated with the temperature of a system is called internal energy, symbolized $E_{int}$?
True
True or false: Gravitational potential energy depends only on the vertical height of the object above the surface of the Earth.
True
True or false: The same amount of work must be done on an object-Earth system whether the object is lifted vertically from the Earth or is pushed starting from the same point up a frictionless incline, ending up at the same height.
True
True or false: The choice of reference configuration for gravitational potential energy is completely arbitrary because the important quantity is the difference in potential energy, and this difference is independent of the choice of reference configuration.
True
True or false: The elastic potential energy of a system can be thought of as the energy stored in the deformed spring.
True
True or false: The elastic potential energy stored in a spring is zero whenever the spring is undeformed (x = 0).
True
True or false: The work done by an applied force Fapp on a block-spring system can be expressed as ΔUs.
True
True or false: Gravitational potential energy depends only on the vertical height of the object above the surface of the Earth.
True
True or false: The same amount of work must be done on an object-Earth system whether the object is lifted vertically from the Earth or is pushed up a frictionless incline, ending up at the same height.
True
True or false: The choice of reference configuration for gravitational potential energy is completely arbitrary.
True
True or false: The elastic potential energy of a system can be thought of as the energy stored in the deformed spring.
True
True or false: The elastic potential energy of a spring is zero when the spring is undeformed.
True
True or false: The elastic potential energy of a deformed spring is always positive.
True
What is the equation for the work done on an object by an agent moving the object through a displacement having both vertical and horizontal components?
$W_{ext} = F_{app} \cdot S_{app}$
What is the equation for the elastic potential energy associated with the block-spring system?
$U_s = \frac{1}{2} kx^2$
What is the equation for gravitational potential energy?
$PE_g = mgh$
What is the classification of the friction force?
Non-conservative force
What is the classification of the gravitational force?
Conservative force
Which type of potential energy depends only on the vertical height of an object above the surface of the Earth?
Gravitational potential energy
What is potential energy?
Potential energy is the energy storage mechanism of a system before it is released.
What is the equation for gravitational potential energy?
$U_g = mgy$
What is the equation for the work done by an external agent on a system?
$W_{ext} = \Delta U_g$
What is the equation for the net work done on a system?
$W_{net} = \Delta KE$
What is the unit of gravitational potential energy?
joules
What does Equation 7.20 represent?
The net external work done on the system appears as a change in the gravitational potential energy of the system.
When is the equation for gravitational potential energy valid?
The equation is valid only for objects near the surface of the Earth, where the acceleration due to gravity is approximately constant.
What principle is described by the equality between the amount of internal energy in the system after the book has stopped and the amount of kinetic energy in the system at the initial instant?
conservation of energy
True or false: The work done by the gravitational force on an object moving downward near the surface of the Earth depends on whether it falls vertically or slides down a sloping incline with friction.
false
What is the classification of the gravitational force?
conservative
True or false: The energy transformation to internal energy due to friction on an incline depends on the distance the object slides.
true
According to the principle of conservation of energy, what is equal to the amount of internal energy in the system after the book has stopped sliding?
the amount of kinetic energy in the system at the initial instant
What is the classification of the friction force?
nonconservative
What is an energy bar chart?
An energy bar chart is a graphical representation of the amount of energy of a given type in a system, with the vertical axis representing the amount of energy and the horizontal axis showing the types of energy.
What is internal energy?
Internal energy is the energy associated with the temperature of a system.
What happens to the kinetic energy when the book is sliding on the surface and slowing down due to friction?
The kinetic energy of the system decreases and is transformed into internal energy.
What type of energy does the system contain when the spring returns to its original length?
When the spring returns to its original length, the system contains only kinetic energy associated with the moving block.
What type of energy does the system possess at the instant the book is released by your hand?
At the instant the book is released by your hand, the system possesses kinetic energy.
What type of energy does the bar chart show decreasing when the block is released and moving to the right while still in contact with the spring?
The bar chart shows the elastic potential energy of the system decreasing when the block is released and moving to the right while still in contact with the spring.
Understanding Work, Energy, and Potential Energy: Test your knowledge on the relationship between work, energy, and potential energy. Explore how work done on a system can result in the appearance of potential energy, and how gravitational potential energy is influenced by the vertical height of an object. Challenge yourself to grasp the concept of work in different scenarios, whether lifting an object vertically or pushing it horizontally.
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