P. Work, energy and power

Question 1

Define the work done on an object by a constant force F

Answer 1

F Δx cos θ , where F is the

magnitude of the force, Δx the magnitude of the displacement and θ the angle
between the force and the displacement.

Question 2

State the work-energy theorem

Answer 2

The net work done on an object is equal to the change in the object’s kinetic energy

Question 3

Define a conservative force

Answer 3

A force for which the work done in moving an object
between two points is independent of the path taken.

Question 4

Define a non-conservative force

Answer 4

A force for which the work done in moving an object
between two points depends on the path taken.

Question 5

State the principle of conservation of mechanical energy:

Answer 5

The total mechanical energy in an isolated system remains constant. A system is isolated when the net external force (excluding the gravitational
force) acting on the system is zero.

Question 6

Define power

Answer 6

The rate at which work is done or energy is expended.