Question

A 596-N physics student stands on a bathroom scale in an 849-kg (including the student) elevator that is supported by a cable. As the elevator starts moving, the scale reads 449 N.

a)Find the magnitude of the acceleration of the elevator.

b) What is the acceleration if the scale reads 659 N ?

c) If the scale reads zero, should the student worry? Explain.

d)What is the tension in the cable in part A?

e)What is the tension in the cable in part C?

Answer 1

G = 9.8 ms^-2 m = 596/9.8 =60.81 kg mg - ma = 449 = ma 596 - 449 = ma a) a = 147/m = 147/6051 = 2.42 ms62 b) a = 659 - 596/6031 = 1.03 ms^2 c) If scale reads zero free fall i.e a = g = 9.8 ms^2 d) Moving down = T = mg - ma = 849 (9.8 - 2.42) = 626562N e) moving up = T = m (g + a) = 849 (9.8 + 1.03) = 9,199.77 N