Energy

Question 1

Define energy

Answer 1

Energy is the capacity to do work

Question 2

What are the pathways for energy transfer

Answer 2

• Mechanically by force acting over a distance
• Heating due to temperature difference
• Propagation of waves
• Electrically by electric current

Question 2

Define internal energy

Answer 2

Internal energy of a substance is the sum of kinetic energy due to random motion of particles and potential energy due to forces of attraction between particles

Question 3

What is dissipation

Answer 3

Dissipation is when energy is converted to less useful forms

Question 4

Define kinetic energy

Answer 4

Kinetic energy is the energy a body possesses due to its motion

Question 5

Define work done

Answer 5

Work done is when energy is transferred mechanically by a force acting over a distance

Question 5

Define gravitational potential energy

Answer 5

Gravitational potential energy is the energy a body possesses due to its position relative to a reference level

Question 6

What is the principle of conservation of energy

Answer 6

Principle of conservation of energy states that energy can neither be created nor destroyed, but can be transferred from one body to another or converted from one form to another

Question 7

Common scenarios for work done

Answer 7

• Against friction
• Against gravity
• Gain in KE
• Gain in GPE

Question 8

What does it mean when an object moves at constant speed

Answer 8

Work done on object by force =
Work done against friction +
Work done against gravity

Question 9

Define power

Answer 9

Power is the rate of work done or the rate of energy transfer