P7 Work, Energy and Power Flashcards

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1
Q

what is work?

A

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

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2
Q

what unit is work measured in?

A

joules (J)

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3
Q

Work = ?

A

force x distance

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4
Q

what is power?

A

the rate at which work done/energy is transferred

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5
Q

what unit is power measured in?

A

watts (W)

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6
Q

Power = ?

A

W/t

E/t

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7
Q

what happens when energy is converted to a different form?

A

some is LOST to surrounding as HEAT/SOUND

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8
Q

what is efficiency?

A

how much energy/power input is converted to useful output

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9
Q

Efficiency = ?

A

useful output / total input

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10
Q

what is GPE?

A

energy due to height

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11
Q

what is KE?

A

energy due to motion

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12
Q

GPE = ?

A

mgh

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13
Q

KE = ?

A

½ mv²

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14
Q

what unit is mass measured in?

A

kg

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15
Q

what unit is gravity measured in?

A

N/kg

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16
Q

what unit is height measured in?

A

m

17
Q

what unit is velocity measured in?

A

m/s

18
Q

what is the law of conservation of energy?

A

energy cannot be created or destroyed, only transformed

→ total input = total output

19
Q

ENERGY TRANSFER BETWEEN GPE & KE:

if air resistance and friction are ignored…

A

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

20
Q

ENERGY TRANSFER BETWEEN GPE & KE:

in reality…

A

GPE also transforms into heat and sound energy (wasted)

→ KE gained < GPE lost

21
Q

list the different types of energy

A

GREEN SHICK

🌎Gravitational potential
☀️Radiant (Light)
🏹Elastic/Strain
🔌Electrical
⚛️Nuclear
🔉Sound
🔥Heat/Thermal
🍵Internal
🍔⛽️Chemical
🏃Kinetic
22
Q

energy can be transformed by?

A
(MELTS)
Mechanical working
Electrical working
Light
Thermal
Sound
23
Q

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

A

geothermal, nuclear, tidal

24
Q

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

A

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

25
Q

list the energy resources

A
⛽️Fossil Fuel
⚛️Nuclear Fission
🌊Hydroelectric(river)
🌊Tidal (sea) 
☀️Solar
🌬Wind
🌋Geothermal
🌲Biomass
26
Q

what are the pros and cons of FOSSIL FUEL?

A

high power output
24 hours

non-renewable
polluting (CO2)

27
Q

what are the pros and cons of NUCLEAR energy?

A

high power output
24 hours

non-renewable
nuclear waste
dangerous
expensive

28
Q

what are the pros and cons of HYDROELECTRIC energy?

A

renewable
non-polluting

blocks rivers
needs big rivers

29
Q

what are the pros and cons of TIDAL energy?

A

renewable
non-polluting

blocks sea areas
needs high tides

30
Q

what are the pros and cons of SOLAR energy?

A

renewable
non-polluting

unreliable
low power output
expensive

31
Q

what are the pros and cons of WIND energy?

A

renewable
non-polluting
cheap

unreliable
low power output

32
Q

what are the pros and cons of GEOTHERMAL energy?

A

renewable
non-polluting
reliable

needs volcano

33
Q

what are the pros and cons of BIOMASS energy?

A

renewable

polluting (CO2)
deforestation