Apparent Weight.? A 550-N physics student stands on a bathroom scale in an elevator that is supported by a cable. The combined mass of student plus elevator is 850 kg. As the elevator starts moving, the scale reads 450 N. (a) Find the acceleration of the elevator (magnitude and direction). (b) What is the acceleration if the scale reads 670 N? (c) If the scale reads zero, should the student worry? Explain. (d) What is the tension in the cable in parts (a) and (c)?

Solution 20E Step 1: Weight of the student on a bathroom scale W 1 = 550 N Combined mass of student and elevator M = 850 kg Problem (a) As the elevator starts moving, find the acceleration of the elevator Step 1: W Mass of the student (m) = g 1 = 59.8 = 56.12 kg