Where do most of the visible electromagnetic waves on earth come from?

Astone dropped into a well is heard to strike the water after 8seconds. find the depth of the well if the velocity of sound is 350m/s

The ability to make things happen is also called a. heat b. force c. matter d. energy

When a pendulum is held high and taut and then is released, the pendulum begins to swing. what’s the correct order of the energy transformations in this example? (pe stands for potential energy.)