physics
posted by Anonymous .
a bus travels from one point to another wuth a speed of 40km/h and returns with a speed of 60km/h.what is e average speed and average velocity of the bus?

since the total displacement vector is zero the average speed is zero.
let i be unit vector from point A to point B
velocity outbound = 40 i
velocity back = 60 i
(40  60)/2 = 10 
The average velocity is zero, but the speed is not.
The total distance covered is 2d. The total time taken is
d/40 + d/60 = 5d/120
So, the average speed is 2d/(5d/120) = 48 km/hr 
Whoops, sorry, Steve is right.