Question

A vehicle travels half the distance L with speed v₁ and the other half with speed v₂. What is the average speed?

Answer 1

Hii friend,

# Answer- 2(v1v2)/(v1+v2)

# Explaination-
In first half, (v=v1, s=L/2),
t1 = s/v
t1 = L/2v1

In second half, (v=v2, s=L/2),
t2 = s/v
t2 = L/2v2

During full journey, (s=L, t=t1+t2)
v = s/t
v = L/(L/2v1+L/2v2)
v = 1/(1/2v1+1/2v2)
v = 2(v1v2)/(v1+v2)

Hope that helps you...