What would happen to the earth if there were no energy?
things we shut down, many cars would not be able to run and we would melt
What would happen to the amount of energy received from the Sun if the rotation of the Earth changed?
When the Sun runs out of fuel, the Earth would not receive any energy; life could no longer exist on Earth. This isn't likely to happen though: long before that happens, the Sun will get so hot that it will kill any life on Earth. The Sun will also become very large, and it may or may not engulf (swallow) the Earth.