Potential Energy

It is the energy - the ability to do work - stored in an object because of its position.

A weight that is high above your head can be made to exert a force when it falls.  This is a type of

Consider the pendulum in the figure.  Release it.  When the pendulum hits the shoe, it will push the shoe forward, exerting a force on the shoe over a distance.  if we were to multiply the force exerted on the shoe by the distance the shoe moves, we could calculate the amount of work that is done.

The pendulum had the ability to do work on the shoe because when the pendulum was at the raised position it had what type of energy?

An object at a given 1($) has an amount of potential energy (PE) that is equal to the 2($) done in raising it to that 3($).  Or, since the 4($) to lift an object is equal to the object's 5($)

1. What is its potential energy with reference to the floor? 1($) joules
2. How much work can it do when it falls? 2($) joules
3. Suppose the object falls onto a marshmallow on the floor and mashes the marshmallow down 1 centimeter.  What force is exerted by the object on the marshmallow? 3($) N

Suppose that a 5-kg object rests on a table.  You lift it up to the ceiling, which is 2 meters above the table.  What is its potential energy with reference to the table?

PE = 1($) joules