Fossil fuels are extracted from the Earth’s crust through mining or drilling processes. Energy is then released by burning these fuels, converting their chemical energy into heat energy, which is harnessed for various applications such as electricity generation or transportation.

Other sources of energy include fossil fuels such as coal, oil, and natural gas, biomass from organic materials like wood or agricultural waste, wind power, hydroelectric power from flowing water, and geothermal energy from heat within the Earth’s crust.

No, these activities are generally not considered work in daily life, as they are often seen as leisure or relaxation.

In daily life, any useful physical or mental effort, such as chores, studying, or professional tasks, is often considered work.

Climbing stairs or a tree involves exerting force against gravity over a vertical distance, meeting the criteria for work in physics.