Calculate the magnitude of the normal force on a 15.2 kg block in the following circumstances. (Enter your answers in N.) (a) The block is resting on a level surface. N (b) The block is resting on a surface tilted up at a 35.8 angle with respect to the horizontal. N (c) The block is resting on the floor of an elevator that is accelerating upward at 3.53 m/s N (d) The block is on a level surface and a force of 155 N is exerted on it at an angle of 35.8 below the horizontal. N