SYSTEM OF WEIGHTS 497

This demonstrates that the bending moment about A is still further
reduced by a redistribution of the total weight of 20 Ibs. The C. of G. of the

. Moment about A 100 , . _ _ ,

system is———--------— = —=5 feet, so that the system could be

Total weight 20

0

A

\A

t. f t t

S 5 5 $ .

Fig. 16.

balanced at the point G, 5 feet from A. Thus an alteration in the
position of the weights alters the position of the centre of gravity
neglecting the weight of the batten.

Note that in the foregoing examples the clockwise moment about G
is equal and opposite to the anti-clockwise moment about the same
point and the rod will not rotate in either direction—it is in equilibrium.

The problem which presents itself on board ship is to find the shift
of the centre of gravity from a given position when weights are ^added
to, taken from or moved a*bout in the vessel, the method of solution
being the same as in the following co-related examples of a simple rod.

10
Fig. 17.
Example.—(i) Consider again the case of our 8 ft. stick with its
C. of G-. at its middle point G when unloaded. If weights of 4, 6 and
10 Ibs. be placed 23 5 and 7 feet respectively from the end K, find the
distance point G has shifted.