In order to derive the moment-curvature relationship, the analysis will require the use of three coordinates. the x axis extends positive to the right, along the ( ) axis of the beam. It is used to locate the differential element, having an undeformed width dx. The v axis extends ( ) from the x axis. It measures the ( ) of the centroid on the cross-sectional area of the element.
A.
longitudinal, positive upward, displacement
B.
transverse, positive upward, displacement
C.
longitudinal, positive downward, displacement
D.
longitudinal, positive upward, strain