MOTION OF PROJECTILES. 



69 



quires when returning to its starting-point the same velocity 

 as that with which it was projected. The time required 

 for the ascent is hence equal to that of the descent to 

 the point of starting. 



The laws which regulate the motion of bodies pro- 

 jected vertically upwards or downwards retain essen- 

 tially their application to bodies projected laterally, 

 either in a horizontal or oblique direction. But the 

 path of a body laterally projected is not a straight line; 



is a curve called & parabola. A body projected hori- 



78-4 



FIG. 50 (yi^ real size). 



fcontally would continue its motion in this direction, if 

 gravity did not act upon it, and its velocity would also 

 in that case remain uniform. The horizontal motion is 



