Work occurs whenever something is moved and an object is put into motion. The motion of an object is described with three things: position, direction and speed. Forces come into play with work because they push and pull objects. All forces have size and direction. Some, like the pull of gravity toward a black hole, are immense, while others, like the push of an ant on a breadcrumb, are very small. Work is possible because all objects have mechanical energy, including potential (energy based on position) and kinetic (energy of motion) energy. Mechanical energy is transferred from one object to another by pushing or pulling it. How fast these objects move depends on the position they began in and how much force was applied to them.

Which of the following is an example of a situation where work occurs?

A
a glass of water sitting on the counter

B
a leaf resting on a rock

C
a student sitting at a desk

D
a baseball soaring through the air