Simulating a pendulum with a moving pivot point

[mangaluve]

I'm doing some computer graphics and I'm pretty new to physics/mechanics. Right now I'm simulating a pendulum. But now I want to be able to move the pendulum to, the point to which the string is connected (for instance if I hold the pendulum between my fingers and move my hand). Now which forces are acting on the pendulum now, how can I update it's position? I'm simulating everything with a computer, so I want the movements to be arbitrary.

 

[Hootenanny]

I'm doing some computer graphics and I'm pretty new to physics/mechanics. Right now I'm simulating a pendulum. But now I want to be able to move the pendulum to, the point to which the string is connected (for instance if I hold the pendulum between my fingers and move my hand). Now which forces are acting on the pendulum now, how can I update it's position? I'm simulating everything with a computer, so I want the movements to be arbitrary.

Welcome to Physics Forums.

That all depends on the constraints placed on the motion of the pivot. If the pivot is contained to moved with a constant velocity, then the transformation is straight forward. If the pivot is accelerating at a constant rate, then the transformation is still fairly straightforward. If however, the pivot is allowed to accelerate arbitrarily then things could become a little more involved.

 

[mangaluve]

Thanks! Well actually I want to be able to move the pivot around with the mouse..any hints?

 

[csprof2000]

You might want to look into the Lagrangian formalism. It makes these sorts of things a lot easier, and it is especially apt to producing good things for computer simulations.

Using it requires some calculus, but that should be expected.

 

[mangaluve]

Thanks, any good links? Calculus is no problem...
Actually I don't need to get too much and deep information, this is just something I do for fun as a graphical effect