Many physical properties, such as force and mass, cannot be measured directly. Rather, some other physical property is measured and the desired physical property is computed from the results. For example, a bathroom scale does not actually measure mass or "weight," but rather the compression distance of a spring. The numerical values on the scale are calibrated from the compression distance using basic physics principles such as Newton's second law. Coefficients of friction cannot be measured directly. In this problem, we are going to learn how we can indirectly measure the coefficient of kinetic friction between two surfaces by directly measuring the expansion of a spring. Consider a 5.45 kg block that is dragged by a spring on a (relatively) frictionless horizontal surface at constant velocity. Suppose the block reaches a rough patch and the spring stretches by 6.25 cm. Compute the coefficient of kinetic friction / between the block and the rough patch if the spring has a force constant of 172.0 N/m. N =Two blocks are connected by a massless rope over a massless, frictionless pulley, as shown in the figure. The mass of block 2 is my = 12.1 kg, and the coefficient of kinetic friction between block 2 and the incline is #x = 0.200. The angle 0 of the incline is 27.50. If block 2 is moving up the incline at constant speed, what is the mass m, of block 1? 2 m= kgAn Atwood machine consists of two masses hanging from the ends of a rope that passes over a pulley. The masses have the values mi = 28.0 kg and my = 16.0 kg. Assume that the rope and pulley are massless and that there is no friction in the pulley. What is the magnitude of the masses' acceleration a? m, 0 = m/2 What is the magnitude of the tension T in the rope? T = N