modelling : physics II
F = Gm1m2/r2,
F12 = -F21 = Gm1m2r/r3,
- G is the gravitational constant, that is approximately G = 6.67 × 10-11 N m2 kg-2,
- and r is the absolute value of r.
F = C(x-l),
F = C(x- (lx/x)).
- C is the spring constant with unit [kg s-2],
- l is the rest length of the spring, and
- x is the absolute value of x.
- Car simulation to get accurate suspension reactions,
- Cloth simulation. Connect springs over a 2d mesh and you get a very pleasent tissue. Search the web for cloth simulation [verlet integration] to see how this works, or have a look at hugo elias' website.
- Water surface waves. Use a cloth simulation and reduce damping as good as possible and you will get a wavy water surface.
F = C(x-l),
d2x/dt2 = F/m = C/m (x-l).This differential equation leads to an oscillating system with a frequency of
f = √(C/m).
- static friction occurs when two objects are not moving relative to each other (pen on a book).
- dynamic friction occurs when two objects are moving relative to each other and rub together.
- rolling friction occurs when two objects are moving relative to each other and one is rolling on the other.
- air friction, wind resistance occurs when one object is moving in a viscous aether.
Ff = μf Fp,
Fair = -cv.
Fair = -c1v -c2v2 -... .