Quiz 14

Several forces do work, but the net work is zero.

A skier moves down a mountain side at constant speed. Which of the following is true? Only the force pointed uphill do work. There is no work done by any force. Several forces do work, but the net work is zero. Only the forces pointed downhill do work.

Several forces do work, but the net work is zero.

A skier moves down a mountain side at constant speed. Which of the following is true? Only the forces pointed downhill do work. Only the force pointed uphill do work. There is no work done by any force. Several forces do work, but the net work is zero.

the kinetic energy to increase when the potential energy decreases.

For a conservative system, you should expect the kinetic energy to increase when the potential energy decreases. the kinetic energy to decrease when the potential energy decreases. the kinetic energy to increase when the potential energy increases.

True

If only one external force acts on a particle, that particle's kinetic energy must change. True False

the total mechanical energy will not be conserved but the total energy will be.

In an isolated system with nonconservative forces only the total mechanical energy will be conserved. the potential energy and total energy will be conserved. the kinetic energy and total energy will be conserved. the total mechanical energy will not be conserved but the total energy will be.

the total mechanical energy will not be conserved but the total energy will be.

In an isolated system with nonconservative forces the total mechanical energy will not be conserved but the total energy will be. only the total mechanical energy will be conserved. the potential energy and total energy will be conserved. the kinetic energy and total energy will be conserved.

can either add to or take away mechanical energy from a system.

Nonconservative forces Incorrect Response can only take mechanical energy from a system. can only add mechanical energy to a system. can either add to or take away mechanical energy from a system. cannot change the mechanical energy of a system.

True

The fact that friction always does negative work indicates that it is a nonconservative force. True False

can be either positive or negative, depending on the potential energy's zero point.

The total energy of an object is always negative. is always positive. can be either positive or negative, depending on the potential energy's zero point. is negative only if the potential energy's zero point is negative.

is conserved when there are no nonconservative forces present

The total mechanical energy of a system is always conserved. is conserved only if there are nonconservative forces present. cannot be changed by any forces. is conserved when there are no nonconservative forces present

The total mechanical energy stays constant; the kinetic energy is maximum when the potential energy is minimum and vice versa.

Think about an ideal spring (one without friction). The spring is horizontal and is attached to a mass, and they both rest on a frictionless horizontal table. Which of the following statements best describes the behavior of the energy of the spring once the mass has been set in motion? The total mechanical energy stays constant; the kinetic and potential energies are minimum at the same time. The total mechanical energy stays constant; the kinetic energy is maximum when the potential energy is minimum and vice versa. The total mechanical energy stays constant; the kinetic and potential energies are maximum at the same time. The total mechanical energy changes in time; the kinetic energy is maximum when the potential energy is minimum and vice versa.

False

You can define a potential energy for friction. True False