(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

http://img120.imageshack.us/img120/3743/physicsquestionnb9.jpg [Broken]

http://g.imageshack.us/img120/physicsquestionnb9.jpg/1/ [Broken]

3. The attempt at a solution

I'm trying this problem and I'm really not sure if my answers are correct at all.

For part a) I get the kinetic energy = Pt (since it is the electrical energy)

I make 0.5m.v^2=Pt and make v the subject, leaving [itex]v=\sqrt \frac{2pt}{m}[/itex]

Now I hope what I've done so far is okay. For part b to find the acceleration I differentiated the equation I derived above. To do this I wrote the equation as

[itex]v=(\sqrt \frac{2p}{m})t^\frac{1}{2}[/itex]

and so

[itex]dv/dt = \frac{1}{2}(\sqrt \frac{2p}{m})t^\frac{-1}{2}[/itex]

While for the distance, by integration, I got

[itex]s= \frac{2}{3}(\sqrt \frac{2p}{m})t^\frac{3}{2}[/itex]

Im not very confident in my maths so I'd appreciated it if somebody could check whether I got the right results.

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# Energy and mechanics question

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