WORK, ENERGY AND POWER

Question 1

State the work-energy theorem:

Answer 1

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

Question 2

conservative force

Answer 2

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

Question 3

Examples of conservative force

Answer 3

gravitational force,
the elastic force in a spring and electrostatic forces (coulombic forces).

Question 4

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

Examples of non conservative

Answer 5

frictional force, air
resistance, tension in a chord,

Question 6

State the principle of conservation of mechanical energy

Answer 6

The total mechanical energy
(sum of gravitational potential energy and kinetic energy) in an isolated system remains
constant.

Question 7

Define power

Answer 7

the rate at which work is done

Question 8

State the Doppler effect

Answer 8

the change in frequency (or pitch) of the sound detected by
a listener, because the sound source and the listener have different velocities relative to
the medium of sound propagation