Suppose now that the lever is moved to the position denoted by the dotted line m m, and the leverages will be altered; that at end a becoming that denoted by the distance from f to the vertical c, and that for end b being denoted by the distance from f to the vertical d.
This occurs because we are dealing with gravity, which always acts in a vertical line.
Fig. 3352.
A crow bar is an excellent example of the application of the lever. In [Fig. 3352], for example, we have a 1 lb. weight on the long end of the lever, and as we are dealing with a weight, the effective length of the long end of the lever is from the fulcrum f to w, which is divided into 10 equal divisions. The short end of the lever is from f to p, which is equal to one division, hence the 1 lb. is balanced by the 10 lbs.
Fig. 3353.
A simple method of distending power is by means of pulleys or gear wheels. Suppose, for example, that in [Fig. 3353], we have a weight of 12 lbs. suspended from a shaft or drum, whose radius a is 10 inches, and that on the same shaft there is a pulley, whose radius b is 20 inches, and the two weights will balance each other.