Topic 3-conservation of energy

Question 1

GPE ( J)

Answer 1

GPE = mass x gravitational field strength x change in height

Question 2

KE (J)

Answer 2

KE = 1/2 x mass x velocity^2

Question 3

What is a closed system ?

Answer 3

• no external forces acting on it

Question 4

efficiency equation (J)

Answer 4

efficiency = useful energy input/ total energy output

Question 5

Examples of energy sources

Answer 5

• Fossil Fuels
• Nuclear Fuel
• Wind
• Solar etc.

Question 6

Ways to increase efficiency

Answer 6

• reduce waste output e.g. lubrication ( less friction) , thermal insulation ( less heat lost to surroundings)
• recycling waste output e.g.absorbing heat energy

Question 7

What is centripetal force

Answer 7

• force acting on a moving body at an angle to make the body follow a circular or curved path.
• e.g. force of gravity acting on a satellite in orbit

Question 8

speed of sound

Answer 8

340 m/s