Answer
56 Newtons
Work Step by Step
To put the block on the verge of moving means that the force applied is equal to Ff,max or the maximum force of static friction. To find what this force is, we need the value of the normal force and the coefficient of static friction, which we are given. Since the block is at rest (not moving) on a horizontal table, the Normal force balances the weight of the block, which is Fg = mg = 11kg * 9.8 = 108 N. Then, this means that Ff, max = 108*0.52 = 56N.
