A person stands on a scale inside an elevator at rest (see the figure below). The scale reads W = 634 N. W a (a) What is the person's mass? 64.63 kg (b) The elevator accelerates upward momentarily at the rate of a = 4 m/s . What does the scale read then? N (c) The elevator then moves with a steady speed of 4 m/s. What does the scale read now? N