2. 1 a.
The gravitational PE store decreases as the ball drops.
The thermal energy store of ball and surroundings
increases.
Energy is transferred by heating due to friction and
a tiny amount by sound waves
1b.
The chemical energy store of fossil fuels decreases.
The electric current in the heating element transfers
energy increasing the thermal energy stores of the heater
and the surroundings.

3. 2 a. Electric torch:
Chemical PE store decreases
Electric current in the wires transfers the energy to
increase the thermal energy store of the surroundings.
( Light waves also transfer energy)
2 a. Candle flame:
Chemical PE store decreases
Thermal energy store of the surroundings increases
by conduction convection and radiation.
( Light waves are also produced )
2b.
It is easier to get the energy from a candle lame, but a torch is easier to use.

4. 3 a. Electric train going up a hill at a steady speed:
KE store stays constant
The electric current in the wires transfers energy to the train , increasing its GPE
and increasing the thermal energy store of the surroundings .
3 b. Electric train braking:
KE store decreases
The thermal energy store of the braking system and the surroundings increases.
4. Heating food in a micro wave oven:
Chemical energy store from fossil fuels decreases
The electric current in the ‘magnetron ‘ transfers
energy by microwaves to increase the thermal energy store of the food and the surroundings