49.(Pg. [66]) How does its power increase?

50.(Pg. [67]) Why is it rather a compound than a simple power?

51.(Pg. [67]) What common instruments act upon the principle of the inclined plane, or the wedge?

52.(Pg. [67]) Why does a knife cut best when drawn across?

53.(Pg. [67]) The screw has two essential parts; what are they?

54.(Pg. [67]) What other instrument is used to turn the screw?

55.(Pg. [67]) How can you compare the screw with an inclined plane? [Fig. 10.]

56.(Pg. [68]) By what two means may the power of the screw be increased?

57.(Pg. [68]) How do we estimate the power gained by the screw?

58.(Pg. [68]) Is the lever always attached to the nut, as in the figure?