Practise energy transfers, stores, resources, efficiency, work and power through calculations, diagrams and explanations of real systems.
A student stretches a rubber band.
The photographs show a rubber band before and after it has been stretched.
before
after
State which energy store increases in the rubber band after it has been stretched.
State the main method of energy transfer when the rubber band is stretched.
State the source of the energy transferred to the rubber band.
A student uses this apparatus to investigate the force needed to pull a block along a ramp.
State the formula linking work done, force and distance moved in the direction of the force.
The student pulls the block 0.89 m along the ramp with a force of 26 N . Show that the work done on the block by the 26 N force is about 23 J .
The block has a mass of 1.3 kg and moves vertically upwards 0.11 m.
Calculate the increase in the gravitational potential energy (GPE) store of the block between the bottom and the top of the ramp.
increase in GPE = ............ J
Explain why the work done to move the block along the ramp is greater than the increase in the GPE store of the block.
The student suggests it is better to use a less steep ramp to raise the block through the same vertical height.
Discuss an advantage and a disadvantage of using a less steep ramp.
The diagram shows a fossil fuel power station.
Five stages of electricity generation and transmission are shown.
The power station burns a fossil fuel in the furnace.
Give an example of a fossil fuel.
Which stage of the power station transfers energy from a chemical store to a thermal store?
condenser
furnace and boiler
generator
turbines
Which stage of the power station transfers energy electrically from a kinetic energy store?
condenser
furnace and boiler
generator
turbines
Electricity can also be generated by solar farms.
Energy is transferred from the Sun to the solar farm by radiation.
The solar farm uses photovoltaic cells to transfer this energy electrically.
Discuss the advantages and disadvantages of generating electricity using solar farms.
The photograph shows a toy car. When the toy car is pulled backwards, energy is stored in the elastic store as the rubber band is twisted.
When the car is released, some of the energy from the elastic store is transferred to the kinetic store of the car.
The remaining energy is transferred into the thermal store of the surroundings.
State what is meant by the principle of conservation of energy.
The car is pulled backwards so that there is 165 J of energy in its elastic store.
When the car is released, this energy is transferred to the car's kinetic energy store with an efficiency of 15\%.
State the formula linking efficiency, useful energy output and total energy output.
Calculate the energy transferred into the thermal store of the surroundings.
energy transferred to thermal store = ............ J
Draw a labelled Sankey diagram for this energy transfer.
The car is pulled backwards again.
When released, 45 J of energy transfers into the car's kinetic store.
The car travels a distance of 7.5 m during this energy transfer.
State the useful work done on the car.
work done = ............ J
Calculate the mean accelerating force acting on the car.
accelerating force = ............ N
