SHIFT OF CENTRE OF GRAVITY 499

ft

??

IO 6

Fig 19

Moment about JT=(4 XlO)+(5 X 6)-= 70 foot-ihs.
70
16

Distance # £3 = — = 4-38 feet

K G2 = 3-90

Lifting ofi the weight has shifted the C. of G. 48 feet or 5-76 inches
to the right. -

Note.—Multiply decimals of a foot by 12 to convert into inches.

Example.—(i) Given a rod of negligible weight, loads of 10 Ibs. and
5 Ibs. are suspended at 2 feet and 8 feet respectively from a point K at
one end of the rod. Find the position of the centre of gravity of the
system (Figure 20).

T

LI*
Fig. 20.
Moment about Z=(2 XlO)+(Sx5)=60 foot-lbs.
60
Distance K G — --=4 feet
15
(ii) Adding weights.—A load of 10 Ibs. is now suspended 7 feet from
. find the position of the new centre of gravity (Figure 21).
Moment about K ==(2xlO)+(7xlO)-f (8x5)
=130 foot-lbs.