Question

An elevator descends into a mineshaft at the rate of 6 m/min. If the descent starts from 10 m above the ground level, how long will it take to reach -350 m.

Answer 1

Initial height = +10 m
Final depth= - 350 m
Total distance to be descended by the elevator = (- 350) - (+10) = -360 m.
Now it is given that the elevator descends at a rate of 6 m/min
So the rate can be considered as a negative quantity.
Thus, time taken by the elevator to descend
= (-360) $÷$ (-6)
= 60 minutes
= 1 hour