3.2 Energy and Power

Question 1

Work is measured in:

Answer 1

Joules (J)

Question 2

1 Joule of work is done when:

Answer 2

A force of 1N moves an object 1m in the direction of the force.

Question 3

Equasion for Work Done (W):

Answer 3

Work Done = Force x Distance (W = fd)

Question 4

Work Done =

Answer 4

Energy Transferred

Question 5

Energy Stores

Answer 5

• Kinetic
• Gravitational
• Elastic
• Chemical
• Electrostatic
• Nuclear
• Thermal
• Magnetic

Question 6

Law of Conservation of Energy

Answer 6

Energy cannot be created or destroyed, only transferred.

Question 7

Formual for Kinetic Energy (KE)

Answer 7

Kinetic Energy = 1/2 x mass x velocity^2 (KE = 1/2 mv^2)

Question 8

Formula for Gravitational Energy (PE)

Answer 8

Gravitational Energy = mass x gravity x height (PE = mgh)

Question 9

Energy Pathways

Answer 9

• Mechanical
• Electrical
• Thermal
• Radiation

Question 10

Formual for Efficiency

Answer 10

Efficiency = Useful Work Done / Total Energy Input

Question 11

Power:

Answer 11

The rate at which work is done. Measured in Watts (W)

Question 12

1W=

Answer 12

1J/s of work being done.

Question 13

Equasion for Power:

Answer 13

Work Done / Time Taken

Question 14

Equasipon for Useful Power Output:

Answer 14

Force x speed