P7

Question 1

what is work

Answer 1

the amount of energy transferred

Question 2

what is the equation for work

Answer 2

work = force * distance

Question 3

what is the unit for work

Answer 3

joules

Question 4

what is the unit for force

Answer 4

newtons

Question 5

what is the unit for distance

Answer 5

metres

Question 6

what is power

Answer 6

the rate at which energy is transferred/supplied

Question 7

what is the equation for power

Answer 7

power = energy/time

Question 8

what is the unit for power

Answer 8

watts

Question 9

what is the unit for energy

Answer 9

joules

Question 10

what is the acronym for energy stores

Answer 10

green sick

Question 11

what are the energy stores

Answer 11

• gravitational potential
• radiant (light)
• electrical
• elastic potential (strain)
• nuclear
• sound
• internal (thermal)
• chemical
• kinetic

Question 12

how is energy transferred between stores

Answer 12

• forces (mechanical work done)
• electrical currents (electrical work done)
• heating
• electromagnetic/sound/other waves

Question 13

what is the principle of conservation of energy

Answer 13

energy can neither be created nor destroyed, only be converted from one form to another

Question 14

what is the equation for kinetic energy

Answer 14

KE = 1/2* mv^2

Question 15

what is the equation for gravitational potential energy

Answer 15

gpe= mgh

Question 16

how is efficiency calculated form energy and power

Answer 16

(useful energy output/energy input) *100%

(useful power output/power input) *100%

Question 17

what is the spring constant

Answer 17

force per unit extension

Question 18

what is hooke’s law

Answer 18

extension of elastic object is directly proportional to load force being applied

Question 19

what is equation for spring constant

Answer 19

k = F/x

Question 20

what is the limit of proportionality

Answer 20

the “limit” force that can be applied before F & x stop being directly proportional

Question 21

how to work out spring constant on graph

Answer 21

gradient

Question 22

examples of renewable energy sources

Answer 22

• wind
• geothermal
• water (wave, hydroelectric, tidal)
• biomass/biofuel
• heat/light from sun

Question 23

examples of non-renewable energy sources

Answer 23

• fossil fuels
• nuclear fission

Question 24

how is energy obtained from chemical energy stored in fuel

Answer 24

• set on fire
• which boils water to spin turbine
• or used in combustion engine

Question 25

how is energy obtained from waves

Answer 25

- buoy bobs up and down on waves - turns turbines

Question 26

how is energy obtained from tides

Answer 26

- flow of water turns generator

Question 27

how is energy obtained from hydroelectric dams

Answer 27

- water flows downhill (gpe-->ke) - spins turbine

Question 28

how is energy obtained from geothermal resources

Answer 28

- heat from earth evaporates water - spins turbine

Question 29

how is energy obtained from nuclear fission

Answer 29

- nuclear fuel rods get hot - heat gas (often water) to spin turbine

Question 30

how is energy obtained from heat and light from sun

Answer 30

- cells: sunlight creates voltage across semiconductor material - panels: sunshine heats water in tank

Question 31

how is energy obtained from wind

Answer 31

- as wind passes, spins turbine

Question 32

what are the steps in a power generator

Answer 32

- boiler: chemical to internal - turbine: internal to kinetic - generator: kinetic to electrical - transformer: change voltage

Question 33

what are advantages of fossil fuels

Answer 33

- easy to use (burn it) - can be transported to where needed - cheap

Question 34

disadvantages of fossil fuels

Answer 34

- burning releases greenhouse gases: global warming - harm environment (oil spills, soot from coal)

Question 35

advantages of wave energy

Answer 35

- plentiful space out at sea - renewable - plentiful in windy places

Question 36

disadvantages of wave energy

Answer 36

- seawater corrodes machinery, maintenance challenging - far away from cities/industries

Question 37

advantages of tidal energy

Answer 37

- reliable: happens every day as earth turns - renewable - no harmful gases produced

Question 38

disadvantages of tidal energy

Answer 38

- require suitable location - expensive to build

Question 39

advantages of hydroelectric dams

Answer 39

- renewable - very short start-up/response time

Question 40

disadvantages of hydroelectric dams

Answer 40

- location dependent (hilly, wet places, not flat) - can be expensive to initially construct)

Question 41

advantages of geothermal energy

Answer 41

free and renewable - no greenhouse gases

Question 42

disadvantages of geothermal energy

Answer 42

- dependent on location - hot areas more accessible in tectonically active places - initial cost to build infrastructure

Question 43

advantages of nuclear fission

Answer 43

- high energy density - no greenhouse gases produce

Question 44

disadvantages of nuclear fission

Answer 44

- radioactive waste - expensive to build

Question 45

advantages of heat and light energy from sun

Answer 45

- sunlight free and reliable in some places - easy to install

Question 46

disadvantages of heat and light energy from sun

Answer 46

- require large surface area to provide reasonable amount of power

Question 47

advantages of wind energy

Answer 47

- renewable - works well anywhere with wind

Question 48

disadvantages of wind energy

Answer 48

- dependent on wind - moderately expensive to build

Question 49

what is the source of tidal energy

Answer 49

moon

Question 50

which energy resources have the sun as the source

Answer 50

all except tidal, geothermal, nuclear

Question 51

how is energy released in the sun

Answer 51

nuclear fusion