Question

You dive a car 2.0 h at 40km/h , then 2.0 h at 60 km/h
A) what is you average velocity
B) do you get the same answer if you drive 100 km at each of the two speeds above

Answer 1

A. d = 40*2 + 60*2 = 200 km.
Vavg = 200/4 = 50 km/h.

Answer 2

B. d1 = 40*T1 = 100.
T1 = 2.5 h.

d2 = 60*T2 = 100.
T2 = 1.7 h,

Vavg. = (d1+d2)/(T1+T2) = 200/4.2 = 47.6 km/h.