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Commit | Line | Data |
---|---|---|
1 | # Harmonic Oscillator | |
2 | # A mass m is subject to a force F=-k*r. | |
3 | # What is the trajectory if the mass starts at position (a,0,0)? | |
4 | # How much time does it take to pass through zero? | |
5 | # What is the trajectory if it starts at (a,0,0) with velocity (0,v0,0)? | |
6 | # Compare to the case including gravity on earth in x direction | |
7 | # m*x'' = -k*x + g | |
8 | # m*y'' = -k*y (z can be set to 0). | |
9 | ||
10 | coefficient.1(-1) -> -a # (a,0,0), has to be negative because x' is negative | |
11 | coefficient.2 -> k/m_x # k/m for x | |
12 | coefficient.3(+1) -> v0 # (0,v0,0), has to be positive because y'' is positive | |
13 | coefficient.4 -> k/m_y # k/m for y, identical to k/m for x | |
14 | coefficient.5(-1) -> -g # g | |
15 | ||
16 | iintegrate x'' -> -x' | |
17 | iintegrate -x' -> x | |
18 | IC: -a | |
19 | cmultiply (k/m_x, x) -> k/m*x | |
20 | isum (k/m*x, -g) -> -k/m*x+g | |
21 | assign (-k/m*x+g) -> x'' | |
22 | ||
23 | iintegrate y'' -> -y' | |
24 | IC: v0 | |
25 | iintegrate -y' -> y | |
26 | cmultiply (k/m_y, y) -> k/m*y | |
27 | invert (k/m*y) -> -k/m*y | |
28 | assign (-k/m*y) -> y'' | |
29 | ||
30 | output x -> out.x | |
31 | output.y -> out.y |