(a) A block with a mass m is pulled along a horizontal surface for a distance x by a constant force F at an angle 8 with respect to the horizontal. The coefficient of kinetic friction between block and table is up . Is the force exerted by friction equal to u mg? If not, what is the force exerted by friction? (Assume 0 is measured above the horizontal.) This answer has not been graded yet. (b) How much work is done by the friction force and by F? (Don't forget the signs. Use the following as necessary: F for the magnitude of F , g, m, x, 0 and uk.) WE WE (c) Identify all the forces that do no work on the block. (Select all that apply.) OF cos(8) OF sin(0) friction f k On (d) Let m = 2.00 kg, x = 3.30 m, 0 = 3.80, F = 18.0 N, and MK = 0.400, and find the answers to parts (a) and (b). (Include appropriate signs.) N WE Jn N FSino FCOSO K - 21 Vertically: N+ Fsino = mg work done by pulling force N = mg-Fsino WF _- FCOSOx Frictional force FR = MKN wonk done W=-fKI for = MK mg - Fsino ) Work done by frictional forces = - fix - - MK/ mg - Fsin@jac WAR = - MK (mg - Fsino) x, (d ) WIK = - fK x = - MK mg - Fsino) c Ansenting all numerical 2 - 0:400 2x9 . 81 - 18.0 sin 3 . 8 X 3- 30 work done by WHY = - 24 . 32 J friction without round figure Ans' WEK = - 2 4 . 323 7 3 4 265 J