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NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE

Arm X power=armx weight, 6xP=2xl05 .-. P=35 Ibs.
Conversely, working in the other direction using B's shoulder as a
fulcrum.

Arm xpower=armx weight 6xP=4xl05 /. P=70 Ibs.

Answer.—B carries 35 Ibs ; A carries 70 Ibs.

The Wheel and Axle is an application of the law of moments. A
dolly winch consists of a wooden barrel of small diameter with a turning
handle of larger radius fitted on the end of a spindle through its centre

Fig. 11.
as in Figure 11, (i), (ii) being an enlarged end section of the winch. The
fulcrum (F) is the spindle, F W is the radius of the barrel, F P is the
radius of the* circle described by the handle, W is the weight to be
lifted, P is the power applied to tne handle.
Arm X weight = arm X power
or, FW xW = FP xP
Example.—The radius of the barrel of a hand winch is 6 inches,
the radius of the handle is 18 inches, find what weight will be sustained
by a force of 100 Ibs. applied to the handle.
6 ins.xTF=18 ins. X100 Ibs. .-. TF=300 Ibs., the weight which
could be held in suspension.
Example.—The radius of a capstan is 1 foot, there are 8 capstan
bars each 6 feet long measured from the spindle of the capstan when
shipped. A weight of 2 tons is being heaved in on a single wire, find the
power to be applied to each bar to hold the weight.
f PxP=F Wx W, or 6 ft. xP lbs.=l ft. X 4480 l"bs.-. P=747 Ibs,
The power on each bar is therefore 747-f8=93f Ibs., neglecting friction.