Work, Power and Efficiency

Question 1

How is work done?

Answer 1

When force is applied and an object moves a distance. This transfers energy

Question 2

What is a joule?

Answer 2

1 joule is the energy transferred when a force of 1N causes a displacement of 1m

Question 3

What properties does a moving object have?

Answer 3

Mass and velocity

Question 4

Gravitational field strength of Earth

Answer 4

9.8 N/kg

Question 5

Gravitational field strength of the Moon

Answer 5

1.6 N/kg

Question 6

What is power?

Answer 6

The rate of transferring energy, also known as the rate of doing work.

Question 7

What is a Watt?

Answer 7

1 Watt is equal to a transfer of J/s

Question 8

What do we mean for a device to be efficient?

Answer 8

If a device is efficient it transfers its energy usefully.

Question 9

If a device is inefficient what does it do?

Answer 9

If a device is inefficient it loses energy to the surroundings (usually by heating), we call this energy dissipated or wasted, as it is transferred to less useful stores