Question

Suppose we represent the distance above the ground by a positive integer and that below the ground by a negative integer. An elevator descends into a mine shaft at 5m per minute. If begins to descend from 15 m above the ground, what will be its position after 17 minutes.

Answer 1

Answer:

Since downwards is negative, the velocity of the elevator is -5 m/min.

However, since we started 15 m above ground, displacement from the ground level = -225 + 15 m = -210 m.