A block rests on a rough floor while a horizontal force F is exerted on it. The frictional force f acting on the block due to the floor is recorded for various values of F , and a graph is plotted between the two variables.

Step-by-step solution

When the applied horizontal force F is less than the limiting static friction, the block remains at rest. In this region, the static frictional force f adjusts itself to be equal in magnitude to the applied force F . Thus, f = F , which represents a straight line passing through the origin with a slope of 45^ . When F exceeds the limiting static friction f_ s, max , the block begins to slide. The frictional force then becomes kinetic friction f_ k . Since the coefficient of kinetic friction _ k is generally slightl