How is energy dissipated to the surroundings?

For a system in which energy is conserved, how are the total energy in, useful energy out, and wasted energy related?

An electric motor has a total energy input of 500 J and a useful energy output of 120 J. Calculate the wasted energy.

True or False? Given enough time, energy in a closed system can eventually be destroyed.

A rollercoaster starts at a raised point and travels down to flat ground. Describe the changes to its energy stores as it does so.

Define the efficiency of a system.

How is efficiency calculated?

True or False? Efficiency has units.

An electric motor has an efficiency of 35% and a useful power output of 280 W. Calculate the total power input.

True or False? If an energy transfer is 65% efficient, then 35% of the energy is wasted.

What does it mean if a system has a low efficiency?

What are fossil fuels?

What are the three main fossil fuels?

True or False? Burning fossil fuels produces only carbon dioxide.

What is a disadvantage of using fossil fuels?

What are the main uses of fossil fuels?

True or False? It takes millions of years for fossil fuels to form.

What energy store is energy transferred from in the combustion of fossil fuels?

How are biofuels produced?

What are the main advantage of using biofuels?

True or False? Nuclear power stations release no pollution into the atmosphere during normal operation.

What is nuclear fuel?

What is the process by which nuclear power stations generate electricity?

Why is nuclear fuel a non-renewable resource?

What is a solar cell?

Which three energy resources do not come from the Sun?

How is solar energy transferred to the Earth?

What is the difference between a solar cell and a solar panel?

What are the main advantages of solar energy?

True or False? Solar panels produce greenhouse gases and pollution.

How do solar furnaces generate electricity?

How does a hydroelectric dam generate electricity?

What is the main advantage of hydroelectric power?

What is the main disadvantage of building a hydroelectric dam?

What is wave power?

What is tidal power?

How do wave and tidal power stations generate electricity?

Give one advantage and one disadvantage of wave and tidal power.

What is a wind farm?

How do wind turbines generate electricity?

True or False? Wind power provides a consistent, reliable supply of electricity.

Give one advantage of wind power.

Give one disadvantage of wind power.

What is a renewable energy source?

What is a non-renewable energy source?

Name two non-renewable energy sources.

Name three renewable energy sources.

True or False? Once set up, all renewable energy resources produce no greenhouse gas emissions at all.

Burning fossil fuels releases greenhouse gases, which contribute to ______, and sulphur dioxide, which causes ______.

Give one reason why countries are increasingly using renewable energy resources.

Define energy stores.

True or False? Energy is measured in units of kilograms.

Define a system in physics.

True or False? Magnetic and electrostatic are examples of energy stores used in physics.

True or False? Objects have energy in their elastic potential store if they are stretched, squashed or bent.

True or False? All objects have energy in their thermal store, the hotter the object, the less energy it has in this store.

What is the definition of energy transfer pathways?

True or False? Energy is transferred only through mechanical pathways.

Define mechanical working in terms of energy transfer.

True or False? In a falling object, energy is transferred from its kinetic store to its gravitational potential store.

State the four energy transfer pathways used in physics.

True or False? An example of energy transfer by heating is a hot chocolate warming up cold hands.

What is geothermal energy?

True or False? Geothermal energy is a non-renewable resource.

What is the main advantage of geothermal energy?

What is the main disadvantage of geothermal energy?

How does geothermal energy generate electricity?

What type of energy resource is geothermal energy?

Define gravitational potential energy.

What is the equation for calculating the change in gravitational potential energy?

If an object falls, energy is transferred ______ its gravitational potential store.

What is the change in gravitational potential energy when a 5 kg object is raised by 2 m? Use g = 9.8 N/kg

True or False? An object gains energy in its gravitational potential store as it falls.

What happens to the energy in an object's gravitational potential store as the object is lifted?

Define kinetic energy.

What is the equation for calculating kinetic energy?

When calculating kinetic energy, remember to ______ the speed before multiplying by half the mass.

What is the kinetic energy of a 2 kg object moving at 4 m/s?

True or False? Doubling an object's speed doubles its kinetic energy.

True or False? A stationary object has energy in its kinetic energy store.

Define power.

True or False? Power is the total amount of energy transferred.

True or False? A car has more power if it does the same amount of work in a longer amount of time.

What is the formula for calculating power?

Define the rate of doing work.

True or False? Power and work done are the same quantities.

State the equation for calculating energy transferred using power.

True or False? Power is often measured in joules (J).

Define work done.

What is the equation for work done?

True or False? The amount of energy transferred is equal to the work done.

A car's brakes apply a force of 500 N, bringing the car to a stop after 23 m. Calculate the work done by the brakes.

True or False? If a force is applied to an object but the object does not move, work is done on the object.

If a force acts in the opposite direction to an object's motion, what happens to the object's energy?