The ring R in the arrangement shown can slide along a smooth, fixed, horizontal rod XY. If is attached to the block B by a light sring. The blocks is released from rest, with the string horizontal.
A. One point in the string will have only vertical motion
B. R and B will always have momenta of the same magnitude
C. When the string becomes vertical, the speeds of R and B will be inversely proportional to their masses
D. R will lose contact with the rod at some point
