A man walks on a straight road from his home to a market 2.5 km away with a speed of 5km h−1. Finding the market closed, he instantly turns and walks back home with a speed of 7.5km h−1. What is the
[Note: You will appreciate from this exercise why it is better to define average speed as total path length divided by time, and not as magnitude of average velocity. You would not like to tell the tired man on his return home that his average speed was zero!]
(a) Magnitude of average velocity of the man over the interval of time (i) 0 to 30 min, (ii) 0 to 50 min, (iii) 0 to 40 min.
(b) Average speed of the man over the interval of time (i) 0 to 30 min, (ii) 0 to 50 min, (iii) 0 to 40 min.