182. Explain by the figures the operation of compound levers.
183. State the comparison between the lever and the wheel and axle. What is said of the common windlass?
184. Describe and explain the capstan. What are its chief uses? What is said of the fusee of a watch?
185. Describe the arrangement of the fixed pulley. What are its uses?
186. Describe the arrangement of the movable pulley. Show how the relation of the power to the weight is estimated in the case of compound pulleys.
187. Explain the mechanical advantage of the inclined plane. Give examples of it.
188. What is said of roads? Give the comparison of the wedge to the inclined plane. How is the power of the wedge estimated? Give examples of the wedge.
189. What is said of the screw? Show by Fig. 180 how the force of the screw is estimated. What are some of the uses of the screw?
190. Give the estimate of the power of the screw and lever as used together. How can you show that there are really but three mechanical powers? What is said of these as composing tools and machinery? What is said of friction in machinery?
191. What is the first advantage of the mechanical powers which is mentioned? Give the illustrations. What is the second advantage? Give the illustrations.