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Bodies thrown Horizontally

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-44

2025-10-23

754

The path of a projectile may be obtained by combining the uniform motion due to the impulsive force with the motion due to the force of gravity; and since gravity is a constant force, the body will generally move in a curved path. The path of a body thrown horizontally may be constructed graphically as follows (neglecting the resistance of the air).

Take the axes as in Fig.1. Let æ represent horizontal motion and y vertical motion. Suppose the horizontal velocity is 50 ft. per second. Compute the values of S from the formula S = 1/2 gf², and determine the position of the projectile at the end of each. second. A curve joining the positions will represent the path required; if the page is held in a vertical plane, the curve is the path in miniature. This curve is of the form called parabolic.

Demonstration. - Fix a sheet of cross section paper to the apparatus shown in Fig. 2 by the clips on the board and fasten a sheet of carbon tracing paper in contact with it. Project a steel ball from its support and it will roll down the inclined plane. Remove the tracing paper and note the relation between the horizontal and vertical velocities. Change the inclination of the plane and repeat.

FIG.1.

FIG.2.