Question

A drunk person moves such that after three consecutive steps forward he takes one step backwards. There is a ditch 10 m away from him when he starts moving in its direction. If his each step is 1 m long and he takes 1 sec to take each step, his average velocity till he falls in ditch is [step in which he falls should not be counted]

• A. $\frac{10}{17}$ m/s
• B. $\frac{1}{2}$ m/s
• C. $1$ m/s
• D. $\frac{5}{9}$ m/s

Answer 1

The correct option is D $\frac{5}{9}$ m/s


$<v>=\frac{Displacement}{time}\Rightarrow Displacement=10m$
For every 2m forward, the time taken is 4 sec. This happens upto 8m. After 8 m, he takes two steps to fall into the ditch.
So time $4\times 4+2=18sec$
$<v>=\frac{10}{18}m/s=\frac{5}{9}m/s$