A force is a push or a pull.

When we say that there is a
** force** on an object we mean that there is a

The metric unit for force is a Newton, English is pound.

In the
** metric** system forces are measured in units of

In the ** English** system forces are measured in units of

A Newton of force is much smaller than a pound of force. It takes about 4.5 Newtons to equal a force of one pound. So, if you usually state your weight in pounds, then you could figure your weight in the Newtons by multiplying those pounds by 4.5.

Forces are vectors.

Forces are vectors. That is, they are quantities that have both
** size** and

Forces can be symbolized with ** arrows**,
as can all vectors. The arrow in the picture below is meant to show a force with the size of 15 Newtons directed
toward the left.

One must understand vectors to understand forces.