An elevator descends into a mine shaft at the rate of 5 metres per minute. If it begins to descend from 15 metres above the ground, what will position after 45 minutes?

(i) Displacement = Velocity x Time = -5 m/min x 60 min = -300 m.

(ii) Displacement from initial position = Velocity x Time = -5 m/min x 45 min = -225 m.

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