Question

the forces on the table act on a ring but are said to be concurrent. if the cords were rigidly to the ring would the forces necessarily be concurrent??

will you please give me some explanation answers about this...thanks a lot..

Answer 1

Concurrent forces pass through the same point. Three forces that are in equilibrium must be concurrent. (Otherwise, there will be an unbalanced moment about some point where two intersect).

See
http://mypages.iit.edu/~krawczyk/phdsza/02conc.htm
for an explanation