Module 3.3

Question 1

Conservation of energy

Answer 1

In a closed system with no external forces the total energy of the system before an event is equal to the total energy of the system after the event. The energy does not need to be in the same form after the event as it was before the event.

Question 2

Efficiency

Answer 2

The useful output of a system divided by the total output

Question 3

Gravitational potential energy

Answer 3

The energy gained by an object when it is raised by a height in a gravitational field

Question 4

Kinetic energy

Answer 4

The energy an object has due to its motion. It is the amount of energy that would be transferred form the object when it decelerates to rest

Question 5

Power

Answer 5

The work down or energy transferred by a system divided by the time taken for that to be done

Question 6

Work done

Answer 6

The energy transferred when a force moves an object over a distance

Question 7

what are all the forms of energy and what do they mean

Answer 7

• Kinetic – the energy associated with the motion of an object with mass.
• Gravitational potential – the energy stored by an object at a point in a gravitational field
• Elastic potential – the energy stored as a result of a reversible change in an object’s
  shape.
• Electric potential – the energy of charges due to their position in an electric field.
• Sound – the energy of a mechanical wave due to the movement of atoms.
• Internal – the sum of the randomly distributed kinetic and potential energies of the
  molecules in a substance.
• Electromagnetic – the energy from electromagnetic waves, stored within oscillating
  fields.
• Nuclear – the energy stored in nuclei, released when particles in nuclei rearrange
• Chemical – the energy contained in chemical bonds, released when atoms rearrange.

Question 8

What is the principle of conservation of energy

Answer 8

in a closed system, energy cannot be created or destroyed, but only transferred from
one form to another

Question 9

How is energy exchanged between Kinetic and gravitational potential

Answer 9

When an object is moving up and down in a gravitational field its kinetic and gravitational potential energy exchange several times. If we consider this
as a closed loop system with no external energy transfer then we can equate the formulas for both. It then shows that the mass of an object has no bearing on its final speed