tolerate that: when, on the other hand, the mobile is carried along line ac, since the downward inclination still tends toward the point of departure, the motive force will not permit it unless it is largely weakened: but when it is carried along line ae nearly parallel to the horizon, the mobile can begin to be inclined downward extremely swiftly {1}; for this inclination does not impede the receding from the point [of departure]. </s>
<s id="id.1.2.10.04.02">But the opposite of this takes place when the mobile is moved on various inclined planes: for on planes that are more inclined the mobile is moved farther by the same force on a straight line, than in planes more upright. </s>
<s id="id.1.2.10.04.03">The reason is that, the more the plane is inclined, the less the mobile exerts weight on it, because a part of its heaviness is sustained by the plane; from this it results that it can be moved more easily by the mover: and, since on the said planes the mobile cannot deviate from its motion except by turning back along the same line, it will be moved farther in a straight line on those planes on which the heaviness of the mobile that must be impelled is less. </s>
