Question

An auto travels the first halftime with a uniform speed u and the next halftime with a uniform speed v. Find its average speed.

• A.
• B.
• C. 2uv
• D. uv

Answer 1

The correct option is A

Step: Express total distance in terms of speed and time.

Total distance $=d=u\times$ $\frac{T}{2}+v\times \frac{T}{2}$

$d=\frac{T}{2}(u+v)$

Total time = T

$V_{av}$ = $\frac{d}{T}$

$=\frac{\frac{T}{2}(u+v)}{T}$

$=\frac{u+v}{2}$