282 APPLIED MECHANICS 
about to break on the tight side? The breaking strength of a 14 inch hemp 
rope may be taken as 18,000 lbs., and 4=0°4. Prove.the 
formula you employ. [U.L.] 
36. A brake strap (Fig. 443) 4 inch thick, embracing 
two-thirds of the circumference of a pulley 16 inches in 
diameter, has one end attached to the end B of a lever 
whose fulcrum is at ©. The other end of the strap is 
attached to the leverat C. AC=15 inches. BC=3 inches. 
A weight W hangs by a rope § inch in diameter, which is 
coiled round a barrel 10 inches in diameter. The pulley 
and barrel are fixed to the same axle. BD is perpendicular 
to AB. The weight W is held up by a force P of 50 lbs. 
acting at A at right angles to AB. Taking 4=0-2, find 
the greatest value of W (a) when the weight hangs as 
Fia. 443. 
shown, (b) when the weight hangs from the other side of the barrel. 
