. Practical physics. Fig. 138. llav .scales Fig. 139. Windlass with shears 6. The hay scales shown in Fig. 138 consist of a compound lever withfulcrums at F, F, F, F. If Fo and Fo are lengths of 6 in., FF andFE 5 ft., Fn 1 ft., Fm 6 ft., rF 2 in., and FS 20 in., how manypounds at W will be required to balance a weight of a ton on the platform? POWER AND ENERGY 121. 7. In. the windlass of Fig. 139 the crank handle has a length of2 ft., and the barrel a diameter of 8 in. There are 20 cogs in the smallcogwheel and 60 in the large one. What is the mechanical advantageof the arrangement ? 8. If in
. Practical physics. Fig. 138. llav .scales Fig. 139. Windlass with shears 6. The hay scales shown in Fig. 138 consist of a compound lever withfulcrums at F, F, F, F. If Fo and Fo are lengths of 6 in., FF andFE 5 ft., Fn 1 ft., Fm 6 ft., rF 2 in., and FS 20 in., how manypounds at W will be required to balance a weight of a ton on the platform? POWER AND ENERGY 121. 7. In. the windlass of Fig. 139 the crank handle has a length of2 ft., and the barrel a diameter of 8 in. There are 20 cogs in the smallcogwheel and 60 in the large one. What is the mechanical advantageof the arrangement ? 8. If in the crane of Fig. 140 the crank arm has a length of 1 m.,and the gear wheels A, B, C, and D have-respectively 12, 48, 12, and 00cogs, while the axle overwhich the chain runs hasa radius of 10 cm., what isthe mechanical advantageof the crane ? 9. If a worm wheel(Fig. 135) has 30 teeth,and the crank is 25 , while the radius ofthe axle is 3 cm., what isthe mechanical advantageof the arrangement ? 10. A small jackscrewhas 20 threads to the a lever 3^ in. longwill give what mechanicaladvantage? (Use ) 11. The screw of a letter press has 5 threads to the inch, and thediameter of the wheel is 12 in. If there were no friction, what jires-sure would result from a rotating force of 20 lb. applied to the wheel ? 12. Eight jackscrews, each of w
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectphysics, bookyear1922
