1) Determine the distance y to the centroid of the beam’s cross-sectional area; then find the
moment of inertia about the centroidal x’ and y’ axis.
2) The object suspended at E weighs 200 lb. Determine the reactions on member ACD at A and
C.
3) The ladder and the person weigh 30 lb and 180 lb, respectively. The center of mass of the 12-ft
ladder is at its midpoint. The angle α= 30°. Assume that the wall exerts a negligible friction
force on the ladder.
(a) If x = 4 ft, what is the magnitude of the friction force exerted on the ladder by the floor?
(b) What minimum coefficient of static friction between the ladder and the floor is necessary
for the person to be able to climb to the top of the ladder without slipping?
4) The concrete “gravity” dam is held in place by its own weight. If the density of concrete is 𝜌𝐶 =
2.5 Mg/m3, and water has a density of 𝜌𝑤 = 1.0 Mg/m3, determine the smallest dimension d that
will prevent the dam from overturning about its end A.