I came across the following problem in an old exam:
How many degrees of freedom does a system of 4 mass points (A,B,C,D) have, if the distances AB, BC and CD are given?
So my attempt was to say particle A can move freely and has therefore 3 DOF, particle B is then constrained by the distance AB can only rotate around A, and has therefore 2 DOF. The same then applies for C and D. So in total I would have 3+2+2+2=9 degrees of freedom, is this a correct approach?
I would really appreciate your help and advice on this particular problem (but maybe also from a more general perspective).