Question

The mass of a lift is $500kg$. What will be the tension in its cable if it moves down with an acceleration $2m{s}^{-2}$?

Answer 1

Step 1: Given

The mass of the lift, $m=500kg$

The acceleration of the lift, $a=2m{s}^{-2}$

Step 2: Solution

The net force on the lift $F=T-mg$

Where $T$ is the tension in the lift's cable and $g$is the acceleration due to gravity $(g=10m{s}^{-2})$.

From Newton's second law:

$F=ma$, Where $a$ is the acceleration with which it's going down

⇒ $ma=T-mg$

⇒ $T=m(g+a)$

⇒ $T=500(10+2)$

⇒ $T=6000N$

Then, the tension in the cable is $6000N$.