The inclined plane is simply a flat surface
raised at an angle, like a ramp. It
is a way of lifting a load that would be too heavy to lift straight up.
The angle (the steepness of the inclined plane)
determines how much effort is needed to raise the weight. The steeper the ramp,
the more effort is required.
In the illustration opposite, you would have
to push the box a greater distance when the ramp is at a low angle.
With a steeper ramp, you would have to push
harder - but for a shorter distance.
The ramp makes life easier not by altering the
amount of work that is needed, but by altering the way in which the work is
done. Work has two aspects to it:
the effort that you put in, and the distance over which you maintain the
effort. If the effort increases,
the distance must decrease, and vice versa. This is easiest to understand by looking at two extremes.
Climbing a hill by the steepest route requires the most effort, but the
distance that you have to cover is shortest. Climbing up the gentlest slope
requires the least effort, but the distance is greatest. The work you do is the
same in either case, and equals the effort (the force you exert) multiplied by
the distance over which you maintain the effort. So what you gain in effort, you pay in distance, and vice
versa. This is a basic rule that
is obeyed by many mechanical devices, and it is the reason why the inclined
plane ramp works: it reduces the effort needed to raise an object by increasing
the distance that it moves.