I'm trying to calculate the top speed of a train and I think I'm almost there but I've hit a wall.(adsbygoogle = window.adsbygoogle || []).push({});

I started off by using the equation found at the link below and solved it for V (velocity).

D=.5*PV^2ACd

http://en.wikipedia.org/wiki/Drag_equation

That gives me

V=SQRT((2D)/(PACd))

When I had finished I realized that this only accounts for air drag. Doesn't the mass of the train also play a factor in it's top speed? I'm not saying that drag isn't the biggest problem it faces but I have to believe mass is also a factor.

I'm using the metric system. Could I add the mass of the train in Kilograms to the right side of the original equation and then solve for V again? More or less that would give me...

The force needed=air resistance at velocity + train mass

Thanks,

Al

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# Calculating the top speed of a train (almost there)

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