Final answer:
Less force is needed to move an object up an inclined plane compared to lifting it vertically because the weight is distributed over a longer distance, making the force needed along the incline less than the full weight of the object.
Step-by-step explanation:
Less force is needed to move an object from one height to another using an inclined plane than is needed to lift the object. When an object moves up an inclined plane, the force required to move it is less than the force needed to lift it vertically because the weight of the object is distributed over a longer distance. The gravitational force working against the motion (which equals the weight) is split into two components on an incline: one perpendicular to the surface, and one parallel. The parallel component, which is the one you're working against when moving the object along the inclined plane, is smaller than the full weight of the object. Therefore, using the inclined plane reduces the effective weight that needs to be overcome, hence requiring less force.