Question

After the elevator accelerates, then it moves at a constant speed of 6.0m/s, calculate the tension inthe cable.

Answer 1

We know that

• The mass of the elevator is 5000 kg.

Let's draw a free-body diagram.

As you can observe, there are just two forces involved, the weight of the elevator and the tension force. Let's use Newton's Second Law.

$\begin{gathered} \Sigma F_y=ma_y \\ T-W=ma_y \end{gathered}$

But, W = mg = 5000kg*9.8m/s^2 = 49,000 N, and m = 5000 kg, a = 0 (because the speed is constant).

$\begin{gathered} T-49,000N=5000\operatorname{kg}\cdot0 \\ T=49,000N \end{gathered}$

Therefore, the tension in the cable is 49,000 N.