Question

A free body diagram with 2 force vectors. The first vector is pointing downward, labeled F Subscript g Baseline = 2,940 N. The second vector is pointing upward, labeled F Subscript t Baseline = blank N. The vectors are the same length.
An elevator is accelerating upward 3.5 m/s2 and has a mass of 300 kg. The force of gravity is 2,940 N. What is the tension force pulling the elevator up?

N

Answer 1

Use Newton's 2nd law: upward positive, T - mg = ma, so T = m(a + g).

Given m = 300 kg, a = 3.5 m/s^2, and mg = 2,940 N:
T = 2,940 N + 300(3.5 m/s^2) = 2,940 N + 1,050 N = 3,990 N.

So the tension is 3,990 N upward.