An inclined plane is a simple machine that provides mechanical advantage by reducing the force required to lift an object. However, the reduced force must be applied over a longer distance. The machine consists of a flat surface that is tilted by an angle such that one end of the surface is higher than the other.

For a frictionless inclined plane the amount of effective work done equals the potential energy gained, which is proportional to the vertical displacement $h$, that is,

$W\=mgh$.

On the other hand, the actual work done can be calculated as the product of the force applied and the distance, $l$, traveled along the inclined plane:

$Wequals;{F}_{i}l$.

Since the effective force overcome is the object's weight, ${F}_{o}equals;mg$, the mechanical advantage works out to

$\mathrm{MA}\mathit{}equals;\frac{{F}_{o}}{{F}_{i}}equals;\frac{l}{h}$.

Given that

$\mathrm{sin}\left(\mathrm{\θ}\right)equals;\frac{h}{l}$,

where, $\mathrm{\θ}$ is the angle of inclination, the mechanical advantage can also be represented by:

$\frac{1}{\mathrm{sin}\left(\mathrm{\θ}\right)}$,

With the addition of friction opposing the movement of the mass, the mechanical advantage is reduced as some of the input energy is converted to heat. As a result, more effort is required in order to push the object up the inclined plane.