stored energies - Sp3

Question 1

what is the equation for gravitational potential ?

Answer 1

mass x gravitational field strength x change in vertical height

Question 2

what factors affect kinetic energy stored in an object?

Answer 2

mass and speed

Question 3

what is the equation for kinetic energy?

Answer 3

1/2 x mass x speed

Question 4

Explain with examples, how energy is conserved

Answer 4

the law of conservation of energy sates that energy cannot be created nor destroyed but can change form into other stores. for instance, energy in a motor is transferred from chemical energy into kinetic energy and thermal energy

Question 5

what are the different types of energy stores?

Answer 5

kinetic, thermal, chemical, nuclear, gravitational potential, elastic potential, electrostatic, magnetic

Question 6

give 2 examples of energy being moved through stores

Answer 6

spring: elastic potential -> kinetic

object at high height: gravitational potential -> kinetic (falling)

Question 7

what are energy efficiency diagrams called?

Answer 7

Sankey diagrams

Question 8

how to calculate the percentage of efficient outcome energy?

Answer 8

efficient outcome/total outcome x 100

Question 9

what happens to wasted energy in energy transfers?

Answer 9

the energy turns into different stores (such as heat or sound)

Question 10

explain one way energy is transferred wastefully by a mechanical process

Answer 10

the thermal energy produces from a running engine (any other example is fine! I believe ur right (::)

Question 11

How can we reduce unwanted energy transfers

Answer 11

lubrication to prevent friction, thermal insulation to prevent thermal loss, streamlining for flying objects

Question 12

what is the definition of efficiency?

Answer 12

how good an object is at at transferring energy input into useful energy output

Question 13

how can efficiency be increased?

Answer 13

by reducing unwanted energy transfers

Question 14

Describe the ways in which energy can be transferred by heating

Answer 14

conduction, convection or radiation

Question 15

how to reduce unwanted energy through thermal insulation

Answer 15

double glazing, cavity walls, loft insulation etc

Question 16

what is the definition of thermal conductivity?

Answer 16

the measure of how well a material conducts thermal energy when it’s heated

Question 17

Describe the effects of the thickness and thermal conductivity of the walls of a building on its rate of cooling

Answer 17

the thicker and the lower the thermal conductivity, the slower the rate of cooling and vies vera

Question 18

how do different factors affect the gravitational potential energy stored in an object

Answer 18

the mass of the object, the distance between ground and object - the heavier and the higher, the greater the gravitational potential energy stored

Question 19

describe how different factors affect the kinetic energy stored in an object

Answer 19

mass + speed - the bigger the object and the faster it travels, the more kinetic energy stored

Question 20

list 3 non-renewable energy sources

Answer 20

fossil fuels, nuclear fuel, coal, oil, gas

Question 21

list 2 advantages and disadvantages of non-renewable fuel

Answer 21

advantages: cheap and reliable for current demand
disadvantages: environmental impact and will not last for long future (not sustainable)

Question 22

list 3 renewable energy sources

Answer 22

bio-fuels, wind, sun, hydro-electricity and tides

Question 23

list 2 advantages and disadvantages of renewable fuel

Answer 23

advantages: last a very very long time and do less damage to the environment
disadvantages: expensive and don’t provide much energy so wont always be able to keep up with demand

Question 24

explain how the use of non-renewable energy sources is changing

Answer 24

coal and gas power stations can now re-use wasted heat - making the most of fossil fuels makes them more sustainable and boosts efficiency of resources

Question 25

list 3 renewable energy sources used today

Answer 25

wind mills, solar panels, tidal barrages

Question 26

describe the sources of energy for different renewable resources

Answer 26

plant, wind, solar, tidal

Question 27

describe different ways in which the sources of energies are used

Answer 27

plant matter = bio fuel, wind = wind mills, solar = solar panels, tidal = tidal barrages

Question 28

explain why we cant ONLY use renewable sources

Answer 28

because on cloudy days when the sun isn’t out, solar panels are ineffective, when there is little wind, wind mills are ineffective and so on. there are many natural variables we must depend upon for these energies to provide us. so when these sources do not work to their full amount, we must use fossil fuels etc to keep up with demand

Question 29

how is the use of renewable energy changing?

Answer 29

prices for renewable energy technologies are dropping to make using renewable energy an affordable solution