Mn$_2$(CO)$_{10}$ has a structure with a direct Mn-Mn single bond, ten terminal CO groups, and no bridging CO groups. Each Mn is in a zero oxidation state.
Co$_2$(CO)$_8$ has a more complex structure. It can exist in different isomeric forms. The most common structure involves bridging CO groups and a Co-Co bond. In another form, there are only terminal CO ligands and a Co-Co bond. In either isomeric form, Co$_2$(CO)$_8$ features a metal-metal bond, terminal CO groups, and can have bridging CO groups. Each Co atom is also in the zero oxidation state.
So, the common features are Metal-Metal linkage (A), Terminal CO groups (B), and Metal in zero oxidation state (D).
A bob of heavy mass \(m\) is suspended by a light string of length \(l\). The bob is given a horizontal velocity \(v_0\) as shown in figure. If the string gets slack at some point P making an angle \( \theta \) from the horizontal, the ratio of the speed \(v\) of the bob at point P to its initial speed \(v_0\) is :