Starting from the front door of a ranch house, you walk 60.0 m due east to a windmill, turn around, and then slowly walk 40.0 m west to a bench, where you sit and watch the sunrise. It takes you 28.0 s to walk from the house to the windmill and then 36.0 s to walk from the windmill to the bench. For the entire trip from the front door to the bench, what are your (a) average velocity and (b) average speed?
Solution 5E Let us have a look at the figure below. Let us understand your walk as shown in the figure above. (a) Your displacement = 60 m 40 m = 20 m 20 m is the shortest distance between your door and the bench. Time needed by you to go to the windmill and then back to the bench is = (28.0 + 36.0) s = 64 s Now, Average velocity = Displacement/Time = 20 m/64 s = 0.3125 m/s (b) Total distance covered by you in walking from your house to the windmill and then to the bench is = 60 m + 40 m = 100 m Now, Average speed = Total distance/Time = 100 m/64 s = 1.5625 m/s