Physics:Work

Force and Motion

For matter to move a force must be applied to it.

You can push a bike, a truck can pull a trailer, air can push on the walls of a tire.

If forces are balanced no motion will occur

Forces must be unbalanced for motion to occur

Forces act together to create motion and direction

This is called vector addition:

Work

When force is applied to matter and the matter moves, work is done.

The key is that the matter moves. If it does not move, regardless of how much force is applied, no work is done.

Calculations

Work can be measured if you know two things:

1. how much force is applied, and

2. the distance matter moves

The Formula

Work (W) = Force (F) x Distance (D) or W = FD

Units

The unit for work is joules (j),

the unit for force is newtons (N),

the unit for distance is meters (m).

Understanding a Joule

One joule is equal to one newton-meter.

This means that one joule of work is done if an object is moved one meter with one newton of force.

This is not much work at all - it is equivalent to pushing a CD one meter across a table.