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.
A car moving along a straight highway with speed of 126 km/hr is brought to a stop within a distance of 200 m. What is the retardation of the car (assumed uniform), and how long does it take for the car to stop?
Here,
Initial velocity, u = 126 km/hr = 35m/s
Final velocity, v = 0
Distance travelled, s = 200m
Now using the equation of motion,
v2-u2 = 2as
Substituting the value of v, u and s we get,
(0)2-(35)2 = 2a x 200
a = -3.0625 m/s2
Time taken by the car to stop is given by,