Question $1$

An elevator has stopped between the first and second floors of a building. The cable attached to the elevator weighs $6k\frac{N}{m}$ and is $40$ meters long. The elevator weighs $10kN$ and there are two persons inside the elevator, weighing $1kN$ each. To rescue the students, the elevator must be manually lifted $5$ meters by pulling the cable at the top of the building. How much work must be done to lift the elevator?

Notes:

All weights are given as forces.

If the elevator is lifted by $1m,$ then the length of the cable is $40-1=39m.$ Similarly, for every value of the movement of the cable.