P1 - Conservation and Dissipation of Energy

Question 1

What is the definition of energy

Answer 1

Energy is the ability to do work.

Question 2

State the law of conservation of energy.

Answer 2

Energy cannot be created or destroyed, it can only be transferred from one store to another.

Question 3

What is a closed system?

Answer 3

A closed system is an isolated system where no energy transfers take place.

Question 4

What does work mean in physics?

Answer 4

Work means to move an object with an applied force.

Question 5

What is the equation for work? (State the units)

Answer 5

Work (J) = Force(N) x Distance (m)

Question 6

State the equation for the change in gravitational potential. (State the units)

Answer 6

Change in gravitational potential (J) = mass(Kg) x gravity (N/kg or M/s squared) x change in height (m)

Question 7

What is energy efficiency?

Answer 7

Energy efficiency is a measure of how much energy comes out as a useful output.

Question 8

What is the equation for energy efficiency?

Answer 8

[Useful output energy (J) / total input energy(J)] x100

Question 9

What does power mean in physics?

Answer 9

Power means the rate at which energy is transferred.

Question 10

What is the equation for power? (State the units)

Answer 10

Power(W) = energy(J) / time(s)