P1

Question 1

Energy Stores

Answer 1

Thermal
Kinetic
Gravitational Potential
Elastic potential 
Chemical
Magnetic
Electrostatic 
Nuclear

Question 2

Systems

Answer 2

A single object (e.g. the air in a piston) or
A group of objects (e.g. two colliding vehicles)
Energy is transferred when a system changes
Can be transferred into it away, between different objects or different types of energy stores

Question 3

Closed system

Answer 3

Systems where neither matter nor energy can enter or leave

The net change in the total energy of a closed system is always zero

Question 4

Energy can be transferred by:

Answer 4

Heating: eg boiling water in a kettle- the water is the system. Energy is transferred to the water by heating, into its thermal energy store (temp. rises) .

Question 5

Energy can also be transferred by D

Answer 5

Doing Work. Just another way of saying energy transferred.
Work can be done when current flows or by a force moving an object.
E.g. initial force exerted to throw a ball upwards does work. Energy transfers from the chemical energy store of the persons arm to the kinetic energy store of the ball and arm.

Question 6

Kinetic energy store

Answer 6

Anything moving has energy in its kinetic energy store. Energy is transferred to this store when something speeds up and is transferred away when the object slows down. Energy in the KE store depends on the objects mass and speed, the greater the mass and speed, the more energy there’ll be.

Question 7

Gravitational Potential energy store

Answer 7

Lifting an object requires work. This causes an energy transfer to the GPE store of the raised object.
The amount of energy in a GPE store depends on the object’s mass, height and the strength of the gravitational field the object is in.

Question 8

Falling objects

Answer 8

When something falls, energy from it’s GPE store transfers to its KE store.
Falling object when there’s no air resistance:
Energy lost from GPE store=Energy gained in KE store
Air resistance acts against all falling objects-causes some energy to be transferred to other energy stores.

Question 9

Stretching

Answer 9

Or squashing can transfer energy to its elastic potential energy store.
So long as the limit of proportionality has not been exceeded, energy in the EP energy store of a stretched spring can be found using the equation

Question 10

Specific Heat Capacity

Answer 10

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

Question 11

SHC practical

Answer 11

1. Measure block of material then wrap it in an insulating later to reduce the energy transferred to the surroundings.
2. Measure initial temp. set power supply to 10V, start stopwatch.
3. Current in circuit does work on heater, temp. rises.
4. Take readings every 5 mins

Question 12

SHC practical 2

Answer 12

5. Collect 10 readings, turn off power supply. Using measurement of current and the PD of the power supply, find the power supplied to heater. Use this to find how much energy has been transferred at the time of each temp.
6. Draw the graph and find the gradient.

Question 13

Conservation of energy/power

Answer 13

Energy can be transferred usefully, stored or dissipated, but can never be created/destroyed.

Question 14

Frictional forces

Answer 14

Something moving has at least one frictional force acting against it.
Causes energy to dissipate.
For objects rubbed together: lubricants reduce friction between objects surfaces.
Lubricants are liquid (flow easily)

Question 15

Heating an object - conduction

Answer 15

Energy transfers to KE stores
Particles vibrate more, collide with each other.
During collisions, energy transfers between the particles KE stores.

Question 16

Thermal conductivity

Answer 16

A measure of how fast energy transfers through a material in conduction.
Materials with high thermal conductivity transfer energy between particles at a faster rate.

Question 17

Convection

Answer 17

If particles are free to move (gas/liquid) the particles moving faster means the space between the individual particles increases.
As liquids/gases flow, the warmer and less dense region will rise above denser, cooler regions.
So energetic particles move away from hotter to cooler regions.

Question 18

Insulating homes

Answer 18

Have thick walls that are made from low thermal conductivity materials.
The thicker the wall and the lower their thermal conductivity, the slower the rate of energy transfer will be (building cools down slower)

Question 19

Examples of how to heat the home:

Answer 19

Loft insulation: reduce convection currents.
Double glazing: have an air gap between 2 sheets of glass to prevent energy transfer by conduction through windows.
Draught excluders: reduce energy transfers by convection around doors and windows.

Question 20

Energy resources: Transport

Answer 20

Non renewable: petroleum and diesel powered vehicles use fuel made from oil.
Coal used in steam trains.
Renewable: vehicles running on pure bio fuels

Question 21

Energy resources: Heating

Answer 21

Non renewable: natural gas heats homes.
Coal burnt in fireplaces.
Electric heaters.
Renewable: geothermal (or ground source) heat pump.
Solar water heaters.
Burning biofuel/getting electricity generated from it.

Question 22

Geothermal Power

Answer 22

Possible in volcanic areas.
Source of much of the energy is the slow decay of radioactive elements in the earth.
Does little damage to environment.
Can directly heat buildings or generate energy.
Drawbacks: there aren’t many suitable places for power plants+expensive

Question 23

Hydro-electric power

Answer 23

Build a dam to get it.
Water allowed out through turbines.
Drawbacks: Possible loss of animal habitat, reservoirs are ugly when they dry up. Initial costs are high.
Advantages: Very reliable, no fuel costs, provides an immediate response if there’s drought.

Question 24

Tidal barrages

Answer 24

Big dams built across river estuaries with turbines in them. As tide comes in it fills up the estuary.
Water allowed out at controlled speed.
No pollution
Pretty reliable 
Moderately high initial costs.