Time varying Gravity

I was wondering if it is possible to vary gravity (g) with time? To start with I’ve used the PushUp example in AMMR 1.3.1. I’ve got a vector the length of the number of time steps, to represent ‘g’. I then tried to reference ‘g’ in AnyBodyStudy “Gravity = {0, g[iStep], 0}”. But I receive ERROR(SCR.EXP10) …“argument will not be ready for evaluation until moment 'EvaluationMoment”.

Is this not only because it ‘iStep’ is not loaded at the point it tries to evaluate the above, but also because Gravity must be a constant? Can you suggest a method to resolve this?

Thanks in advance,

Hi Chris,

when you click on Gravity in the ModelTree it tells you that Gravity is a constant. So it is not possible to change gravity.

What you could try is to apply an acceleration to the Centre of Mass (of the Body) instead.

This is just an idea, and I cannot guarantee that this will work.