In an orthogonal cutting operation, consider the following parameters: to = 0.15 mm, V = 2.5 m/s, a = 13, and the width of cut is 4.5 mm. During the operation, it is noted that to = 0.20 mm, F = 500 N, and Ft = 200 N. Calculate the percentage of the total energy that is expended in overcoming friction at the tool-chip interface.