. The elements of railroad engineering . st, // tends to returnto that position. For example, a cube, a cone resting on its base, a pendu-lum, etc. If a body is in stable equilibrium, its center of gravityis raised when it is displaced. 92(). A body is in unstable equilibrium when, ifslightly displaced from its position of rest, // tends to fallfarther from that position. For example, a cone standing upon its point, an eggbalanced upon its end, etc. Any movement, however slight, lowers the center ofgravity when the body is in unstable equilibrium. 921. A body is in neutral equilibrium when it
. The elements of railroad engineering . st, // tends to returnto that position. For example, a cube, a cone resting on its base, a pendu-lum, etc. If a body is in stable equilibrium, its center of gravityis raised when it is displaced. 92(). A body is in unstable equilibrium when, ifslightly displaced from its position of rest, // tends to fallfarther from that position. For example, a cone standing upon its point, an eggbalanced upon its end, etc. Any movement, however slight, lowers the center ofgravity when the body is in unstable equilibrium. 921. A body is in neutral equilibrium when it hasno tendency to move either way, in the direction of its mo-tion, after being slightly displaced. For example, a sphere of uniform density ; a cone restingon its side. 922. A vertical line drawn through the center of gravityof a body is called the line of direction. So long as the lineof direction falls within the base, the body will stand. Whenthe line of direction falls without the base, the body will fall. ELEMENTARY MECHANICS. 335. Let A C B, Fig. 133, be a cylinder whose base is obliqueB B to the center line B O D ; and let Obe the center ofgravity of this cyl-inder. So long as the perpendicular through O falls be- FiG- 133. between A and C, the cylinder will stand, but the instant that it falls without the base, the cylinder will fall. The center of gravity of a body always tends to seek itslowest point. EXAMPLES FOR PRACTICE. 1. There are three weights in a straight line. The first weighs40 lb.; the second, 16 lb., and the third, 50 lb. Distance between the firstand second is 6 ft., and between the second and third, 10 ft. Where isthe center of gravity ? Ans. 8 ft. in. from the 40-lb. weight. 2. Find the perpendicular distance between the center of gravityand the longer side of a triangle whose sides are 7 ft., 10 ft., and 15 Solve graphically. Ans. ft. 3. A rectangle, 2 ft. long and 1 ft. wide, has equal weights of 50 , suspended from two of
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