Question

Suppose the distance above the ground is represented by a positive integer,then that below the ground will be represented by negative number. If an elevator descends into a mine shaft at the rate of 6 metre per minute;what will be it's position after half an hour ?

Answer 1

v=-6m/min=-6m/60s=-0.1m/s
t=0.5 hr=0.5*60*60=1800s
S=v*t=-0.1*1800=-180m
Therefore the elevator will be 180 meters below the ground after half an hour.

Answer 2

1 minute = -6 metre
according to question ,
30 minutes = -6 * 30
                   = -180
so , the elevelator position would be 180 metre below the ground