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thawanikajal · Jul 30, 2010, 10:03 PM

A moving body travels distance d at uniform speed V1, and travel distance d at uniform speed V2 prove that its average speed is 2V1*V2/V1 + V2

Unknown008 · Jul 31, 2010, 01:03 AM

Use the average speed formula.

$Average\ Speed = \frac{Total\ Distance}{Total\ time}$

The distance now, is 2d.

The time, t_1 for the first part of the journey is given by $\frac{d}{v_1}$

That for the second part is given by $\frac{d}{v_2}$

Sub in your equation;

$Average\ Speed = \frac{2d}{\frac{d}{v_1}+\frac{d}{v_2}}$

Now you can simplify :)

[Thanks ebaines for the other one ;)]