Law of Lifting Machine:

The law of the lifting machine is attained by drawing a graph between effort and corresponding load lifted by the machine. Figure illustrates such a graph. The various values of effort and the corresponding loads have been plotted in this figure. The average line AB may be drawn through the points. Mathematically specking, the law of the machine can be represented by a straight line

                               P = m W + C         ----------(1)

Here, m is slope of the line AB and C is the intercept of the line on Y-axis, m and C are constants.