1.
Determine the coordinates of the centroid of the bearrTs cross-sectional area shown in the figurę. Consider the size of the comer welds at A and B for the calculation to be negligible.
1.
150 mm--\
A. y = 172mm from the top
B. y = 185mm from the top|
C. y = 154mm from the top
D. y = 145mm from the top
E. y = 166mm from the top
Solution
The correct answer is C.
The y-axis is an axis of symmetry and the centroid must lie on this axis. Thus, x = 0.
Centroidal y-coordinate:
^ y i • Ai = 7.5 • 15 • 150 + 90 • 150 • 15 + 215 • n • 502 = l,907,981.05?m?i3
= l54mm from the top
y =
^ At = 15 • 150 + 150 • 15 + TT • 502 = 12,353.98mm3 _ E 9 i' A i
E Ai