Physics: Energy (Paper 1)

What is kinetic energy and the formula?

• Energy stored in moving objects

• Stationary objects have no kinetic energy

• Ek = 0.5 x m x v²

What is elastic potential energy?

• Putting energy in to stretch the spring

• The stretched spring is storing the energy as ‘elastic potential energy’

• Extension is directly proportional to force applied

• In metres!

What is work done?

Doing work

Meachnical work: Applying a force to move an object

Energy transferred from one store to another

Electrical work: Current transferring energy

What is gravitational potential energy?

Energy stored in an object sue to its position above the earths surface

What is specific heat capacity?

The amount of energy required to raise the temp of 1kg of the substance by 1ºC

(Given formula in exam)

What is the law of conservation of energy?

Energy can be transferred usefully, stored or dissipated but it cannot be created or destroys

What is energy dissipation?

Energy wasted

e.g. friction transfers energy to thermal energy stores

How is energy transferred in a system?

How is energy transferred in a bungee jump?

1. All energy is GPE

2. As they fall, GPE is transferred to KE

3. Rope tightens, KE is at its max

4. Fully extended, zero kinetic energy

5. All energy EPE

6. Going back up, EPE transferred to KE

7. KE transferred to GPE

8. At the top, all energy is GPE

Never return to original position. Energy is dissipated as thermal energy (friction, stretching effects in elastic)

How can you calculate work done?

How can you calculate the power?

How can you calculate efficiency?

x 100 for percentage

You know you have switched the equation if your answer is more than 1

How can you increase efficiency of an energy transfer?

What factors reduce cooling of a building?

• insulation

• Double glazed windows

• Loft insulation

Specific Heat Capacity Required Practical

1. Record mass of oil in beaker

2. Place thermometer & emersion heater into beaker

3. Wrap beaker in insulating foam

4. Connect joule meter & power pack to emersion heater

5. Time for 30 mins

6. Read total no of joules and temperature

What can affect accuracy in the Specific Heat Capacity Required Practical

Investigating different thermal insulators required practical process & results

1. Small beaker in large beaker

2. Put boiling water into small beaker

3. Put thermometer through cardboard lid

4. Record start temp

5. Start timer

6. Record temp every 3 mins for 15 minutes

7. Repeat with insulating material in large beaker

Results (image)

What are the variables in the thermal insulators required practicals?

IV - Type of insulating material

DV - Temperature

CV - Vol of water, mass of material, temp of water

IV - Number of layers

DV - Temperature

CV - Start temp, vol of water

Investigating (same) thermal insulators required practical process

1. Fill beaker with hot water

2. Put on cardboard lid & Place thermometer in

3. Wrap in 1 layer of newspaper

4. Record start temp, Start timer

5. Record temp envy 3 mins for 15 minutes

6. Repeat with more layers of newspaper

What are the main fossil fuels & what do they do?

• Oil

• Natuaral gas

• Coal

Provide: Transport, generate electricity, heating

What advantages do fossil fuels have?

• Release lots of energy

• Reliable

• Abundant & cheap

• Versatile (portable)

What disadvantages do fossil fuels have?

• Releases lots of CO2

• Non-renewable

• Release other pollutants (health damage)

What is nuclear power advantages & disadvantages?

• Non release CO2

• Reliable

• Dangerous radioactive materials

• Extremely expensive to dismantle

• Radioactive waste

Where does the UK get energy from? Why?

• Coal

• Got replaced by:

• Nuclear power (20%)

• Oil & gas (gas equal to coal use)

Burning gas generates less CO2 than burning coal

Gas-fired power stations are flexible (switched on quickly)

Why can scientist not control how energy resources are used?

• Politicians didn’t worry

• Fossil fuel energy is cheap

• Renewable energy is not reliable

• Use nuclear power & gas

What are renewable sources of energy?

Renewable energy can be replenished as it is being used

Why can solar power not generate all our electricity?

• Cannot run 24/7

• Would need massive amounts of land for the panels

• Low useful power output

What are benefits of electric cars charging as they drive (coils of wire under motorways)

1. Cars dont have to stop to charge

2. More cars can be charged at the same time

How is this a closed system?

The car has 0.20J of GPE at C how much does it need to complete the loop?

• The total energy of the race track and the car is constant

• More than 0.20J

• Because it needs energy to be moving to complete the loop.