Topic 3 Conservation Of Energy(complete)

Question 1

What is formula for gravitational potential energy
GPE

Answer 1

GPE=mass><gravitational><change><g><h</g></change></gravitational>

Question 2

Formula for kinetic energy
KE

Answer 2

Kinetic energy =1/2><mass><velocity^2
KE=1/2><m><v^2</m></mass>

Question 3

What does conservation of energy mean

Answer 3

Energy is never created or destroyed

Question 4

What is energy being used when an ball is being rolled up a slope

Answer 4

Energy transfer from kinetic energy to gravitational potential energy via mechanically

Question 5

What happens to energy when a ball is moving and hitting a wall

Answer 5

Ball contains kinetic energy strode
When ball makes contact with wall some of kinetic energy transfers to thermal energy via mechanical and rest is carried away by sound

Question 6

What happens to energy when a vehicle is slowing down

Answer 6

Energy in kinetic energy store from moving car transfers to thermal energy store due to friction mechanically by the cars wheels and the road

Question 7

What happens to energy when water is boiling in a kettle

Answer 7

Energy transferred from the mains to the heating part of the kettle electrically
Then by heating to the thermal energy store of water

Question 8

What happens to energy when a rock is dropped from a cliff(assuming no air resistance)
(Object accelerated by a constant force)

Answer 8

Energy is transferred from gravitational potential energy to kinetic energy store via mechanically

Question 9

What happens to total energy in a closed system

Answer 9

Total energy doesn’t change in a closed system

Question 10

What is an example of a wasted energy transfer

Answer 10

When energy is transferred mechanically to thermal energy store as waste

Question 11

What are ways of reducing unwanted energy energy transfer

Answer 11

Lubrication
Thermal insulation

Question 12

Is energy transfers some energy is always wasted / dissipated

Question 13

How does lubrication reduce unwanted energy transfers

Answer 13

Reduce friction between objects so less energy transferred to thermal energy store so less unwanted energy

Question 14

What does thermal conductivity mean

Answer 14

How well a material transfers energy through conduction

Question 15

How does building thicker walls in buildings help insulate a building

Answer 15

Thicker walls mean that energy will be transferred more slowly so therefore the building is insulated better

Question 16

What is the formula for efficiency

Answer 16

Efficiency=
useful energy transferred by device/total energy supplied to device

Question 17

What is a non renewable energy source

Answer 17

Means it will eventually run out

Question 18

What is a renewable energy source

Answer 18

Means it will never run out

Question 19

What are the 2 non renewable energy sources we use today

Answer 19

Fossil fuels and nuclear fuel

Question 20

What are some renewable energy sources

Answer 20

Bio fuel
Wind
Hydro electricity
Tides
Sun

Question 21

How does wind power energy work

Answer 21

Use wind turbines to generate electricity
Expensive initial cost but minimal maintenance cost
Dependent on wind

Question 22

How does sun energy work

Answer 22

Use solar cells that are made with materials that use energy transferred by light to create electrical current
No pollution
High initial costs but low maintenance costs
Dependent on sun amount and cannot increase production during demand

Question 23

How are bio fuels used to create energy

Answer 23

Created from plant products or animal dung
Carbon neutral if you burn plants the same rate you are growing them
Reliable
High costs
Need to clear space to grow plants for bio fuels -environmental problems

Question 24

How is hydro electricity used to create energy

Answer 24

Flood valley by building a dam and catch rainwater
Water is allowed through turbines
Big impact on environment
You can increase demand when needed
Initial costs are high but low maintenance costs

Question 25

How are tides used to create energy

Answer 25

Tidal barrages are dams built with river estuaries with turbines
As tide comes in it fills up estuary water let out through turbines
No pollution
Alter habitat
Reliable
Moderately high initial costs low maintenance costs

Question 26

Over 20th century electricity use of UK was very high
21st century electricity use of UK has been decreasing slowly
Trying to increase use of renewable energy sources for non renewable ones for other things like heating cooking fuel

Question 27

We now know that non renewable energy sources have harmful effects on the environment
Government shave made targets for renewable sources
Example of this is using electric cars

Question 28

Renewable sources are usually less available and more expensive
Usually depend many on other things and cannot increase production during high demand
Research into new ways of renewable sources takes time so in mean time non renewable sources are used
Electric cats more expensive
Solar panel more expensive
Price slowly going down