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 1 m long and requires 1 s. Plot the x-t graph of his motion. Determine graphically and otherwise how long the drunkard takes to fall in a pit 13 m away from the start.

Given,


Distance covered in one step = 1 m


Time required for one step = 1 s


Distance for pit from initial position = 13 m


Time taken to move 5m forward = 5 s


Time taken to move 3m backward = 3 s


Speed of the drunkard = 1 m/s (from above two observations)


Net distance covered = 5-3 = 2 m


Net time required to cover 2m = 8 s


Total 6 complete forward-backward cycles possible.


Time taken for 6 cycles = 36 s


Distance covered in 6 cycles = 12 m


Total time required to cover 13 m = 36 + 1 =37 s


The graph obtained from above data is,



10