2 Work, Energy and Power

Question 1

Work Formula

Answer 1

Work done = force x distance moved in direction of force
W = F x d

Question 2

Work SI Units

Answer 2

Joules (J)

Question 3

Work done is equal to …

Answer 3

the energy transformed

Question 4

An object may have energy due to …

Answer 4

its motion (kinetic energy) or its position (potential energy)

Question 5

An object’s energy can be …

Answer 5

transferred and stored

Question 6

Kinetic energy

Answer 6

Energy that is due to motion

Question 7

Potential energy

Answer 7

Energy which an object has because of its changed position, shape or state

Question 8

Gravitational potential energy

Answer 8

The energy stored in objects raised above Earth’s surface, which is due to Earth’s gravitational field

Question 9

Elastic potential energy

Answer 9

The energy stored when an object is being stretched or compressed

Question 10

Chemical potential energy

Answer 10

The energy stored by chemical bonds between atoms

Question 11

Electrical potential energy

Answer 11

In circuits, the current is a flow of electrons, which can transfer energy from, for example, a battery to a light bulb: they have electrical potential energy

Question 12

Nuclear potential energy

Answer 12

The energy stored in the nucleus of an atom

Question 13

Thermal energy

Answer 13

When hot objects cool down, their atoms and molecules slow down and lose energy: this is thermal energy

Question 14

Radiated energy

Answer 14

Light and sound waves are radiated from sources, these carry energy

Question 15

Kinetic energy formula

Answer 15

KE = ½mv 2

Question 16

Gravitational potential energy formula

Answer 16

GPE = mgh

Question 17

Internal energy

Answer 17

The sum of the kinetic and chemical energy of the particles that make up an object

Question 18

Energy is transferred by … (4)

Answer 18

forces (mechanical working), electric currents (electrical working), heating and waves

Question 19

Law of conservation of energy

Answer 19

Energy cannot be made or destroyed, but can change from one form to another.

Question 20

Efficiency equations (3)

Answer 20

Efficiency = useful work done / total energy input
Efficiency = useful energy output / total energy input
Efficiency = useful power output / total power input

Question 21

Force SI units

Answer 21

Newtons (N)

Question 22

Energy SI units

Answer 22

Joules (J)

Question 23

Mass SI units

Answer 23

Kilograms (kg)

Question 24

Weight is a …
Therefore, its SI units are …

Answer 24

force
Newtons (N)

Question 25

Average speed equation

Answer 25

Average speed = distance moved / time taken

Question 26

Acceleration equation

Answer 26

Acceleration = gain in speed / time taken

Question 27

Force equation

Answer 27

Force = mass x acceleration

Question 28

Weight equation

Answer 28

Weight = mass x gravity (10N/kg) W = m x g

Question 29

Power Equation

Answer 29

Power = work done (energy transformed) / time taken P = ΔE / t

Question 30

Renewable Energy Sources (List: 7)

Answer 30

Hydroelectric energy, Tidal energy, Wind energy, Wave energy, Geothermal energy, Solar energy, Biofuels

Question 31

Non-Renewable Energy Sources (List: 2)

Answer 31

Fossil fuels, Nuclear fuels

Question 32

Hydroelectric energy

Answer 32

Water flows down from behind a dam, turning generators

Question 33

Tidal energy

Answer 33

Generators are turned by the tide of water coming in and/or going out

Question 34

Wind energy

Answer 34

Generators are driven by wind turbines

Question 35

Wave energy

Answer 35

Generators are driven by the up-and-down motion of waves at sea

Question 36

Geothermal energy

Answer 36

Means "heat from the Earth" - due to rising steam from water that is pumped down to hot rocks deep underground

Question 37

Solar energy

Answer 37

Solar panels or solar cells absorb the light energy from the sun and use it to heat water or generate an electric current, respectively

Question 38

Biofuels

Answer 38

Fuels made from plant or animal matter, sometimes called biomass, which can be burnt to release energy

Question 39

Fossil fuels

Answer 39

Fuels made from the fossils of plants and animals long ago, which can be burnt to release energy

Question 40

Nuclear fuels

Answer 40

The energy is released by fission, a process in which the nuclei of uranium atoms are split, at nuclear power stations

Question 41

The SUN is the source of energy of all of our energy sources except ...

Answer 41

geothermal, nuclear and tidal

Question 42

The MOON is the source of energy for which energy source?

Answer 42

Tidal

Question 43

Energy is released by what process in the SUN?

Answer 43

Nuclear fusion, a process in which the nuclei of hydrogen atoms are pushed together to form helium

Question 44

Efficiency can be expressed as a percentage by ...

Answer 44

multiplying by 100