When something happens, energy is changed from one form into another. When you climb stairs, chemical energy in your food is changed into kinetic energy by your muscles, and into potential energy as you raise your body against gravity. The amount of energy transferred is measured in JOULES.
Depends which time period. But it's probably the 20th century. The Cold War and WW2 plus others made the US impose democracy and capitalism for other countries.
The purpose of dividing the government into 3 different branches was that so one entity did not have all the power. So they basically did it to divide the power.
