$${\rm I}$$-section of a beam is formed by gluing wooden planks as shown in the figure below. If this beam transmits a constant vertical shear force of $$3000$$ $$N$$, the glue at any of the four joints will be subjected to a shear force (in $$kN$$ per meter length ) of

If a beam of rectangular cross-section is subjected to a vertical shear force $$V,$$ the shear force carried by the upper one-third of the cross-section is