P7 Work, Energy and Power

Question 1

what is work?

Answer 1

ENERGY transferred by a FORCE to MOVE something in the direction of the force

Question 2

what unit is work measured in?

Answer 2

joules (J)

Question 3

Work = ?

Answer 3

force x distance

Question 4

what is power?

Answer 4

the rate at which work done/energy is transferred

Question 5

what unit is power measured in?

Answer 5

watts (W)

Question 6

Power = ?

Answer 6

W/t

E/t

Question 7

what happens when energy is converted to a different form?

Answer 7

some is LOST to surrounding as HEAT/SOUND

Question 8

what is efficiency?

Answer 8

how much energy/power input is converted to useful output

Question 9

Efficiency = ?

Answer 9

useful output / total input

Question 10

what is GPE?

Answer 10

energy due to height

Question 11

what is KE?

Answer 11

energy due to motion

Question 12

GPE = ?

Answer 12

mgh

Question 13

KE = ?

Answer 13

½ mv²

Question 14

what unit is mass measured in?

Answer 14

kg

Question 15

what unit is gravity measured in?

Answer 15

N/kg

Question 16

what unit is height measured in?

Answer 16

m

Question 17

what unit is velocity measured in?

Answer 17

m/s

Question 18

what is the law of conservation of energy?

Answer 18

energy cannot be created or destroyed, only transformed

→ total input = total output

Question 19

ENERGY TRANSFER BETWEEN GPE & KE:

if air resistance and friction are ignored…

Answer 19

GPE at top = KE at bottom
GPE lost = KE gained / KE lost = GPE gained
→ g h = ½ v²

Question 20

ENERGY TRANSFER BETWEEN GPE & KE:

in reality…

Answer 20

GPE also transforms into heat and sound energy (wasted)

→ KE gained < GPE lost

Question 21

list the different types of energy

Answer 21

GREEN SHICK

🌎Gravitational potential
☀️Radiant (Light)
🏹Elastic/Strain
🔌Electrical
⚛️Nuclear
🔉Sound
🔥Heat/Thermal
🍵Internal
🍔⛽️Chemical
🏃Kinetic

Question 22

energy can be transformed by?

Answer 22

(MELTS)
Mechanical working
Electrical working
Light
Thermal
Sound

Question 23

The SUN (nuclear fusion) is the source for all energy resources EXCEPT FOR?

Answer 23

geothermal, nuclear, tidal

Question 24

what is the difference between renewable and non-renewable energy?

Answer 24

R: doesn’t run out
N: will eventually run out

Question 25

list the energy resources

Answer 25

``` ⛽️Fossil Fuel ⚛️Nuclear Fission 🌊Hydroelectric(river) 🌊Tidal (sea) ☀️Solar 🌬Wind 🌋Geothermal 🌲Biomass ```

Question 26

what are the pros and cons of FOSSIL FUEL?

Answer 26

high power output 24 hours non-renewable polluting (CO2)

Question 27

what are the pros and cons of NUCLEAR energy?

Answer 27

high power output 24 hours non-renewable nuclear waste dangerous expensive

Question 28

what are the pros and cons of HYDROELECTRIC energy?

Answer 28

renewable non-polluting blocks rivers needs big rivers

Question 29

what are the pros and cons of TIDAL energy?

Answer 29

renewable non-polluting blocks sea areas needs high tides

Question 30

what are the pros and cons of SOLAR energy?

Answer 30

renewable non-polluting unreliable low power output expensive

Question 31

what are the pros and cons of WIND energy?

Answer 31

renewable non-polluting cheap unreliable low power output

Question 32

what are the pros and cons of GEOTHERMAL energy?

Answer 32

renewable non-polluting reliable needs volcano

Question 33

what are the pros and cons of BIOMASS energy?

Answer 33

renewable polluting (CO2) deforestation