Unwind the paper. a large 16.0-kg roll of paper with radius r = 18.0 cm rests against the wall and is held in place by a bracket attached to a rod through the center of the roll. the rod turns without friction in the bracket, and the moment of inertia of the paper and rod about the axis is 0.260 kgm2 . the other end of the bracket is attached by a frictionless hinge to the wall such that the bracket makes an angle of 30.0◦ with the wall. the weight of the bracket is negligible. the coefficient of kinetic friction between the paper and the wall is µk = 0.25. a constant vertical force f = 60.0 n is applied to the paper, and the paper begins to unroll. what is the initial magnitude of (a) the force that the rod exerts on the paper as it unrolls; (b) the angular acceleration of the roll? (initial because we are calculating this for when the radius is 18 cm and moment of inertia is 0.260 kgm2 .