Question

Part 2 After reaching the top of the incline, the box of mass 1 kg is released, and allowed to slide back down the hill of incline angle 0 20 At the halfway point, the surface of the incline becomes rough, and friction becomes important The coefficients of friction between the box and hill are μ-: 0.7 and μ.-0.5. 0 20 D. Draw a free body diagram for the object as it moves down the incline as it encounters the rough surface. Identify and name all the individual forces acting on the box, including what type of friction. (8 pts) E. Determine the frictional force acting on the box, and explain how you The box is both moving and accelerating at this point (4 pts) Determine the net force acting on the box, and the corresponding acceleration of the 1 kg box. (6 pts) F.

Answer 1

d) The free body diagram is shown below The forces are N = Normal force f_k = kinetic frictional force mg sin theta = gravitational force along horizontal mg cos theta = gravitational force along vertical e) The frictional fore is, f_k = mu_k mg cos theta = (0.5) (1) (9.8) (cos 20) = 4.6044 = 4.6 N f) The net force is, F_net = mg sin theta - f_k = (1) (9.8) (sin 20) - 4.6 = -1.2482N = -1.25 N Since, the frictional force is greater than that of m g sin theta, the box stopped. It will not move and acceleration is zero.