Inclined Plane


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.