Answer:
Explanation:
Speed is total distance traveled over time taken to do so.
If AB is measured in kilometers, time (t) for the whole trip is
t = AB/60 + AB/40
t = 2AB/120 + 3AB/120
t = 5AB/120 hrs
Average speed is distance over time
s = 2AB / (5AB/120)
s = 2(120)/5
s = 48 km/hr
s = 48(1000 m/km / 3600 s/hr) = 13.333333.... 13 m/s
Velocity is displacement over time.
As displacement is zero, velocity is zero
v = 0 km/hr = 0 m/s
Pretty harsh reporting answers just because they are wrong.