P1 ENERGY

Question 1

equation for kinetic energy?

Answer 1

1/2 x mass x (velocity)²

energy = j
mass = kg
velocity = m/s

Question 2

equation for elastic potential energy?

Answer 2

1/2 x spring constant x (extension)²

energy = j
spring constant = n/m
extension = m

Question 3

equation for gravity potential energy?

Answer 3

mgh

mass=kg
energy = j
gravitational field strength = n/kg
height = m

Question 4

define specific heat capacity?

Answer 4

the amount of energy needed to raise the temperature of 1kg of a substance by 1 degree celsius.

Question 5

unit for specific heat capacity?

Answer 5

joules/degree celsius/kilogram

Question 6

power meaning?

Answer 6

the rate at which energy is transferred

Question 7

two equations of power?

Answer 7

power = energy transferred/time
power = work/done

Question 8

power unit?

Answer 8

watt (w)

Question 9

two motors lift the same mass through the same height. motor a does this is half time of motor b. which dissipates the most power?

Answer 9

motor a
the energy transferred is the same but time taken is less

Question 10

describe the energy changes involved when a ball is thrown upwards and then returns to its starting position. ignore air resistance

Answer 10

upwards: ke is converted to gpe
peak : maximum gpe, zero ke
downwards : gpe is converted to ke

Question 11

describe the energy transfer for a bungee jumper?

Answer 11

when falling the gpe is converted to ke of the jumper.
as the cord tightens, ke is converted and stored as elastic potential energy.
at lowest point , the jumper’s initial gpe equals the epe stored in the cloud.

Question 12

explain why a bungee jumper slows down once the cord begins to stretch.

Answer 12

ke decreases since its converted to elastic potential energy.
since ke is proportional to velocity² , as ke decreases so does velocity

Question 13

examples of chemical energy store?

Answer 13

food, fuel , batteries

Question 14

4 different stores of energy?

Answer 14

kinetic energy
gravitational potential energy
elastic potential energy
chemical energy

Question 15

kinetic energy?

Answer 15

energy stored in moving object.

Question 16

elastic potential energy?

Answer 16

A force acting on an object may cause the shape of an object to change.

Question 17

gravitational potential energy?

Answer 17

energy stored in an object due to its position above the earths surface.

Question 18

equation for specific heat capacity?

Answer 18

change in thermal energy = mass x specific heat capacity x temp change

Question 19

law of conservation of energy?

Answer 19

energy can be transferred usefully , stored or dissipated but it cannot be created or destroyed

Question 20

what is a system?

Answer 20

an object or a group of objects

Question 21

what is closed system?

Answer 21

no energy can enter or leave

Question 22

state any changes in the total energy of a ball that is kicked assuming that no external forces act

Answer 22

total energy of the system remains constant due to the conservation of energy.

Question 23

what is waste energy?

Answer 23

energy that is not usefully transferred or transformed.

Question 24

describe the energy changes that occur in a filament light-bulb

Answer 24

electrical energy is transferred into light and heat energy.
light is a useful energy form , heat is waste energy

Question 25

equations for efficiency?

Answer 25

useful output energy transfer / total input energy transfer. useful power output /total power ouput

Question 26

how can the efficiency of a system be increased?

Answer 26

reducing the waste output. recycling waste output

Question 27

state the consequence for energy transfer of a material with high thermal conductivity

Answer 27

energy transfer through the material is higher than for a material with lower thermal conductivity

Question 28

do double glazed windows have higher or lower thermal conductivity than single glazed window

Answer 28

low = less energy transfer through them

Question 29

key factors that affect the rate of cooling of a buliding?

Answer 29

thickness of walls thermal conductivity of the walls

Question 30

3 methods reducing heat loss in a building?

Answer 30

double glazing loft and wall insulation thicker walls

Question 31

thermal conductivity?

Answer 31

the higher the thermal conductivity of a material the higher the rate of energy transfer by conduction across the material.

Question 32

renewable energy?

Answer 32

one that is being replenished as it used

Question 33

examples of renewable energy?

Answer 33

wind power solar power hydroelectric power tidal power

Question 34

an example of non renewable energy?

Answer 34

fossil fuels

Question 35

advantages of generating power using gas rather than coal?

Answer 35

burning gas generates less carbon dioxide than burning coal. gas fired power stations are flexible. they can be switched on quickly during periods of high demand , coal fired power stations have a very long start up time

Question 36

2 disadvantages of using renewable energy resources to generate power?

Answer 36

wind and solar power are not reliable. some days are simple not windy and solar power does not work well on cloudy days. generating power through other means is often more efficient and economically beneficial.

Question 37

the environmental impacts of burning fossil fuels?

Answer 37

carbon dioxide - contributed to the greenhouse effect and causes global warming. sulhur dioxide - leads to acid rain which damage buildings and crops.

Question 38

advantages of fossil fuels?

Answer 38

reliable abundant and cheap release a great deal of energy

Question 39

what is nucleur power

Answer 39

non renewable energy which runs on the elements uranium and plutonium

Question 40

advantages of nucleur power?

Answer 40

once a nucleur power plant is running it releases no carbon dioxide extremely reliable generates lots of electricity exactly when we want

Question 41

disadvantages of nucleur power?

Answer 41

contains highly dangerous radioactive materials , if there is an accident then these materials could release into the environment. decommissioning a nuclear power plant takes many years and is extremely expensive. generates large amounts of highly dangerous radioactive waste , this must be stored for thousands of years before its safe

Question 42

how does hydroelectricty power produce energy?

Answer 42

rainwater collects behind the dam. when this water is released it is used in a turbine. this turbine turns a generator which produces electricity.

Question 43

disadvantages of biofuel?

Answer 43

plants are burned or decay they release carbon dioxide. growing biofuel reduces the land for growing crops. if we use land to grow crops for fuel that coukd push up the price of food.

Question 44

advantages of tidal energy source?

Answer 44

extremely reliable. does not produce carbon dioxide cheaps to run as tides are natural and so are free

Question 45

disadvantages of hydroelectricity power?

Answer 45

Habitats are destroyed when dams are built and valleys are flooded. can cost a lot to install the required infrastructure

Question 46

advantages of solar panels?

Answer 46

never run out no carbon dioxide in the air

Question 47

an example of a social factor which may act as a deterrent for certain types of energy production?

Answer 47

visual pollution sound pollution (disadvantages of wind farms)