1, how much energy is needed to run a 40 watt light for 2 hours.
2. how you can tell coal is a more concentrated store of chemical energy than wood is.
3.why is it that the natural realese of carbon from decaying plant and animal material dose not cause global warming but the realease of carbon dioxide from burning fossil fuels dose.
energy= power*time (change time to seconds).
The energy in coal vs wood is easily seen in a experiment: equal masses of each, and measure the heat coming off.
The natural release actually does contribute, however, it is a steady amount. The use of energy with the burning of fossil fuels is what has changed.