Systems and Objects Physics

Work is done on an object

• whenever a force acts on the object.

• whenever a force is perpendicular to the displacement of the object.

• whenever a force causes a displacement of the object.

• whenever a net force acts on the object.

Tags

NGSS.HS-PS3-1

In which of the following cases is no work done?

• A weightlifter lifts a barbell.

• A weightlifter holds a barbell overhead.

• A weightlifter slowly lowers a barbell.

• A weightlifter drops a barbell and the barbell falls to the ground.

If the sign of work is negative,

• the force is in the same direction as the displacement.

• the force is perpendicular to the displacement.

• the component of the force that does work is in the direction opposite the displacement.

• the component of the force that does work is perpendicular to the displacement.

Tags

NGSS.HS-PS3-1

Energy that is due to the motion of an object is

• kinetic energy.

• potential energy.

• gravitational potential energy.

• elastic potential energy.

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

Energy stored in the gravitational field of interacting bodies is

• kinetic energy.

• nonmechanical energy.

• gravitational potential energy.

• elastic potential energy.

Tags

NGSS.HS-PS3-2

Energy associated with a compressed or stretched object is

• kinetic energy.

• potential energy.

• gravitational potential energy.

• elastic potential energy.

Which of the following is true of the conservation of energy in a closed system?

• Kinetic energy is always conserved.

• Potential energy is always conserved.

• Mechanical energy is always conserved.

• Total energy is always conserved.

The mechanical energy of a system of objects is

• the sum of kinetic energy and gravitational potential energy.

• the sum of kinetic energy and elastic potential energy.

• the sum of kinetic energy and all relevant forms of potential energy.

• the sum of all forms of energy.

Which of the following refers to the rate at which work is done?

• energy

• kinetic energy

• mechanical energy

• power

Which of the following is not a valid equation for power?

• P = W / Δt

• P = Fd / Δt

• P = Fv / Δt

• P = Fv