A 1.4 kg block is initially at rest on a horizontal frictionless surface when a horizontal force in the positive direction of an x axis is applied to the block. The force is given by , where x is in meters and the initial position of the block is x = 0. (a) What is the kinetic energy of the block as it passes through x = 2.8 m? (b) What is the maximum kinetic energy of the block between x = 0 and x = 2.8 m?