Energy is the mover and shaker of the universe. Heat from the Sun, sounds from your radio, riding a bike and watching a movie are all expressions of different forms of energy. As you sit there reading this, there is energy flowing all around you in the form of light waves, sound waves, radio waves, heat and more. You are constantly being bombarded by energy. Energy is everywhere, all the time.
The physics problems we've solved on paper so far have made good use of Newton's Laws of Motion to figure out how a parachutist falls, how fast the airplane goes, or how high a pitcher throws the baseball. But sometimes, Newton's Laws of Motion break when we apply them to certain problems, such as particles moving near the speed of light, or describing the motion of an electron in an atom. Since there's more than one way to climb a mountain, we're going to look at solving physics problems using energy.