A drunkard walking in a narrow lane takes 5 steps forward and 3 steps backward, followed again by 5 steps forward and 3 steps backward, and so on. Each step is `1m` long and requires 1s. Plot the x-t graph of his motion. Determine graphically or otherwise how long the drunkard takes to fall in a pit 9 m away from the start.

Explanation

from x-t graph time taken `=21 s`
OR `(5m-3m)+(5m-3m)+5m=9m rArr` total steps `=21 rArr` time`=21 s`