Physics Examples/Help With Differentials

Sage
Posts: 1,066
Joined: 2004.07
Post: #1
I found a website (http://www.myphysicslab.com) that shows examples of 2D physics systems for a number of objects like springs and rigid bodies. It also explains things with some equations.

I'm currently trying to reproduce the single spring in my program (just learning some physics) but I am a bit rusty on differentials. I took very little calculus so I'm not very good with figuring out some of the things.

When it says
x'' = -k/m*x - b/m*x'
is that the same as
a = -k/m*x - b/m*v?

If so could I handle the position as follows (I intialized x = 4 and v = 0)?
Code:
```    float m = .5; //mass     float R = 2.5; //length of spring at rest     float k = 3; //spring stiffness     float b = .1; //damping constant          float a = -(k/m) * x - (b/m) * v;     v += a;     x += v;```

Thanks for any help.
Moderator
Posts: 608
Joined: 2002.04
Post: #2
Nick Wrote:When it says
x'' = -k/m*x - b/m*x'
is that the same as
a = -k/m*x - b/m*v?
If x is the position function then yes, x'' would be acceleration.

Possibly Related Threads...
 Thread: Author Replies: Views: Last Post Porting examples from an introductory 3D book crazy_ut2k4 4 4,897 Feb 16, 2007 08:04 AM Last Post: AnotherJake Bullet Physics Library / COLLADA physics viewer erwincoumans 14 19,277 Aug 12, 2006 12:59 AM Last Post: Fenris NSAffineTransform Examples dancedrummer 2 7,761 Jul 1, 2005 09:34 PM Last Post: dancedrummer