1. To find the average speed. Let ‘s’ is the distance between the home and the office.
∴ Time taken to reach the office
t1 (distance/velocity) = s/2
Similarly, time taken to walk back to the home from the office is t2 = s/4
∴ Total time taken = t1 + t2 = s/2 + s/4 = 3s/4
Total distance moved = s + s = 2s
Hence. the average speed = total distance moved/total time taken
= 2s/(t1 + t2) = (2s/3s/4) = 8/3
= 2.67 ms-1
2. To find the average velocity Since the man comes back to home, the final and initial position is same.
∴ Total displacement is zero.
Hence average velocity = total displacement/time taken
= 0