You've always wondered about the acceleration of the elevators in the 101-story-tall Empire State Building. One day, while visiting New York, you take your bathroom scales into the elevator and stand on them. The scales read 150 lb as the door closes. The reading varies between 120 lb and 170 lb as the elevator travels 101 floors. 

a. What is the magnitude of the acceleration as the elevator starts upward? 

b. What is the magnitude of the acceleration as the elevator brakes to a stop?