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Don't panic!* Morten Dam Jørgensen - Computerfysik.dk

Don't panic!* Morten Dam Jørgensen - Computerfysik.dk

Don't panic!* Morten Dam Jørgensen - Computerfysik.dk

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• Spørgsmål:<br />

Hvis vi ville indføre<br />

luftmodstand (drag),<br />

hvordan skulle vi bære os<br />

ad?<br />

⇢<br />

~v<br />

Cd<br />

A<br />

~Fdrag = 1<br />

Densitet af mediet (luft)<br />

2 ⇢~v2 CdA<br />

Hastigheden af legemet relativt til mediet<br />

Drag koefficient (dimensionsløs)<br />

Tværsnittet af objektet i bevægelsesretningen<br />

http://en.wikipedia.org/wiki/Drag_(physics)<br />

Frit fald<br />

g = -9.8;<br />

y0 = 100; v0 = 0; % start<br />

y = y0; v = v0; % sæt start<br />

t = 0; dt = 0.1; % tid<br />

% Euler metoden<br />

while y > 0 % stop ved y=0<br />

t = t + dt;<br />

y = y + v .* dt;<br />

v = v + g .* dt;<br />

plot(t,y,'b+')<br />

end

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