Recent content by Patrikp

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    Doppler effect for accelerated source

    Ok, but is the above formula correct in this case or is just approximation? Can you help me derive it in this specific case?
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    Doppler effect for accelerated source

    I don`t understand why this formula works in this case. Can you describe mathematically why does it work even though the source accelerates? That`s my problem.
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    Doppler effect for accelerated source

    I don´t understand. Can you describe that mathematically?
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    Doppler effect for accelerated source

    No, that is not the issue. I am having trouble understanding why this formula works even when the source is accelerating ( does not have constant velocity ).
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    Doppler effect for accelerated source

    Homework Statement At the initial moment source and detector are located in same point and are both in rest. Source is released into free fall and detector remains in rest. Source has frequency fs=512 Hz and speed of sound is v=340 m/s . When detector detects frquency f =485 Hz , what...
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    Capacitance of four metal plates

    Can you explain how did you get that? Thanks
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    Capacitance of four metal plates

    Homework Statement Four identical parallel metal plates with area $$S$$ and distance between each two $$d$$ are located in air. The external plates are connected by wire. What is the equivalent capacitance between A and B? This is problem from Irodov.Homework Equations $$q=UC$$[/B]The Attempt...
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    What Happens to a Partially Inserted Dielectric in a Capacitor?

    1. The problem statement, Dielectric plate is placed in capacitor to the half(picture) and it can freely move. Capacitor consists of two parallel plates and is isolated. Consider two cases: a)charges on plates are constant, b)voltage is constant. What happens in each case? 2. Homework...
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    Find k & a for Infinite Distance Travel w/ Drag Force F=kv^a

    Ok I see why a=1 doesn't work now...
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    Find k & a for Infinite Distance Travel w/ Drag Force F=kv^a

    How did you get this?
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    Find k & a for Infinite Distance Travel w/ Drag Force F=kv^a

    Homework Statement Only force acting on body is drag force $$F=kv^a$$ where k is constant, a coefficient bigger than zero and v is velocity. Body is given initial velocity u. Find a such that body travels infinitely large distance.[/B]Homework Equations $$F=kv^a$$ $$F=m(acceleration)$$...
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    Pressure caused by explosion in closed container

    This is a problem from competition that is not over yet.
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    Min Friction Factor to Maintain Angle of Beam on Wall: 60°

    That's even better, thanks.
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    Min Friction Factor to Maintain Angle of Beam on Wall: 60°

    Ok, I know that net torque of all forces and net force must be zero. I draw the following forces: 1)gravitational force of beam (located in the middle of beam) 2)gravitational force of body ( exactly where the body is) 3) friction (acts horizontally?) Then, I tried to write these forces as...
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    Min Friction Factor to Maintain Angle of Beam on Wall: 60°

    Ahh...I have problems translating it in English, I understand it. Anyways I thought of force x distance whatever it is called. I will edit it now.