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The Inclined Plane

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-108

2025-12-30

1082

Any plane surface that makes an angle with a horizontal surface form an inclined plane. A ball placed upon a horizontal plane will retain its position and will press upon the plane with its entire weight. As soon, however, as one end of the plane is raised, the entire weight of the ball will not rest upon the plane, and it will begin to roll toward the lower end. The only way in which an inclined plane can be used efficiently is to have the moving

Fig. 1

force act in a direction that is parallel to the inclined surface of the plane. Inclined planes are used for the purpose of lifting a weight to a certain height by the use of a small power. The power which moves a body from the bottom of the plane to the top lifts it through the height of the plane against gravity and hence the general law of machines will apply. This may be modified to read

PL = WH, whence P: W = H: L,

in which H is the vertical height of the plane and L is the length along the slope .

A demonstration of the law of the inclined plane can be made with an apparatus like that shown in Fig. 1. The cylinder is the weight and the pull of the power is made parallel to the plane by means of the cord running over the fixed pulley at the top.