Recent content by Maor Hadad

Hi, It's: A Question About Partial Derivatives, thanks a lot!

Hi, I understand now what my problem was. I can also 'see' why it's true through the algebra, but I think the fact the independent variable is a derivatie of time, makes it a bit un-intuitiable for me. I tried plotting it but it came as something ##\delta## like, so it didn't helped so much...

Yes, you're right. It dosen't! my professor accidently wrote it as: \frac{\dot{q}}{\sqrt{1+\left(\dot{q}\right)}} and that's how I tried to solve it... thank you!

If you mean \left(\frac{\dot{q}}{const}\right)^{2}-\dot{q}-1=0\Rightarrow? It's by dividing two sides by const and multiplying by \sqrt{1+\left(\dot{q}\right)^{2}} and than squaring both sides. If I'll continue I'll need to solve quadratic equation which it's results will depend on the...

Homework Statement \frac{d}{dt}\left(\frac{\dot{q}}{\sqrt{1+\left(\dot{q}\right)^{2}}}\right)=0\Rightarrow\frac{\dot{q}}{\sqrt{1+\left(\dot{q}\right)^{2}}}=const\Rightarrow\dot{q}=A\Rightarrow q=At+B Homework Equations Why it ok to say that...

Homework Statement v_{i}=\dot{x}_{i}=\dot{x}_{i}\left(q_{1},q_{2},..,q_{n},t\right) T \equiv \frac{1}{2}\cdot{\sum}m_{i}v_{i}^{2} \frac{\partial T}{\partial\dot{q}_{k}}={\sum}m_{i}v_{i}\frac{\partial v_{i}}{\partial\dot{q}_{k}}={\sum}m_{i}v_{i}\frac{\partial x_{i}}{\partial q_{k}}[/B]...

Thank you, Perhaps you can explain what's the 'physical principles' behind that?

Of course it does :smile: But speaking in energetic terms - is the work (Force*Length [Joule]) will be the same, no matter what's the configuration of the engine comparing to the wagons? If so, why did the 'Push-Pull' train was invented? Couldn't they just leave the engine in the rear part...

Hi, I have a question about where's the most efficient place for a train engine - Let's say a train has to do a some route back and forth, the route has curves and positive and negative slopes. In real life - What's the best position for the enginge? My intuition says it will be most efficient...