(1) In science we describe energy an agent changing the position or form
of things.
2) Energy is needed to bring about changes to objects and to the
movements of objects. For example
A-A football moves when a player supplies energy to a foot ball by his foot
B- A fan moves when electrical energy is supplied.
C- A car moves with the energy of petrol
D- lce melts when heat energy is supplied.
(3) Therefore we can say that energy is the ability of a body or a thing to
do work.
(4) When we say that a body has energy, we mean that it has the ability of
doing work.

Potential energy

(1) Consider a stone is in your hand. Is this stone able to do something to
other objects?

(2) The answer is no, least not while it is in your hand.
(3) Suppose you throw it. If it strikes to a glass of a windows, it can break
the glass.
4) While the stone was lying in your hand, it had potential energy. It was
only necessary to throw the stone to strike to the glass gaining kinetic
energy as it stroke.
(5) Every object that is in a position from where it can fall or move has
potential energy due to its position.
6) Some more examples of potential energy are given below.

A- When the girls is sitting on the top of the slide and not sliding, she has

potential energy due to her position.
B-A book lying on the table has potential energy due to its position.
C-The spring of a watch when wound up has potential energy due to change of its shoupe

Leave a Reply

Your email address will not be published. Required fields are marked *