10.energy and work Flashcards
energy can also be expressed in other than joul
ergs ,calories ,british thermal nits ,killowatt hours ,kilocalories
w=
w=Fs
Which of the following conditions must be met for work to be done?
A. Force must be applied, and the object must remain stationary.
B. Force must be applied, and displacement must occur in the direction of the force.
C. Displacement must occur, but force is not required.
D. Only potential energy must be involved.
B. Force must be applied, and displacement must occur in the direction of the force.
The work done by a force is zero when:
A. The force acts in the direction of motion.
B. The force is perpendicular to the direction of displacement.
C. The force acts against the direction of motion.
D. The displacement is zero.
B. The force is perpendicular to the direction of displacement.
correct expression for kinetic energy?
KE= 1/2 mv 2
Potential energy of a body is given by:
PE=mgh
The power of a machine can be defined as:
A. The total work it can perform in one second.
B. The total energy consumed by it in one hour.
C. The maximum force it can exert.
D. The efficiency with which it converts potential energy into kinetic energy.
A. The total work it can perform in one second.
Work-energy theorem states that:
A. Work done on an object is equal to the change in kinetic energy of the object.
B. Work done on an object is equal to the change in potential energy of the object.
C. Total work done is equal to the sum of potential and kinetic energy.
D. Work done is independent of the energy change in the system.
A. Work done on an object is equal to the change in kinetic energy of the object.
What happens to the energy of a system when work is done against friction?
A. It is converted entirely into potential energy.
B. It is converted entirely into kinetic energy.
C. It is lost as heat energy.
D. It remains unchanged.
C. It is lost as heat energy.
