Unhelpful detailed derivations for DblPend

[samm82]

Some of the GDs in DblPend have detailed derivations that just restate the relevant equation with no elaboration:

Are there actually detailed derivations that should be present in these models, or can these derivations just be removed?

[smiths]

Unfortunately the equation isn't correct for GD:yForce1. It is supposed to be a vertical force, so it should be the y-component of the force vector, not the full vector. It shouldn't be the vector T1 (and T2) multiplied by the cosine of the angles; it should be the magnitude of the vector T1 (and T2). For m1*g, it shouldn't be the vector g, but the y component of the vector g.

When we add in the notion of vector and finding the components of the vector, we'll probably need the detailed derivation. I think we can leave the detailed derivation as a placeholder for now.

We should check over the theories in the double pendulum example, but before we do so, we really need to add more knowledge on vectors to double pendulum. We have the same problem with the projectile example. It is probably best to wait for the refined theories version of Drasil to facilitate managing the knowledge on vectors.