6-29. Determine the force in members HG, HE and DE of the truss, and state if the members are in tension or compression. G 4 ft 3 ft

*6-12. Locate the centroid I of the area.

Two uniform spheres are positioned as shown. Determine the gravitational force F which the titanium sphere exerts on the copper sphere. The value of R is 55 mm. Copper y T 2.1 R j) (10-8) N R 4.6 R Titanium Answer: F = (i 26° - X i + i

Two uniform spheres are positioned as shown. Determine the gravitational force F which the titanium sphere exerts on the copper sphere. The value of R is 30 mm. y Copper T 2.5 R x i + i j) (10-8) N R 4.9 R Titanium Answer: F = (i 27°

*6-4. Locate the centroid I of the area. y = -b-

*9-72. The cylinder CD af the assembly is heated from T, = 30 °C to T, = 180 °C using electrical resistance. At the lower temperature T, the gap between C and the rigid bar is 0.7 mm. Determine the force in rods AB and EF caused by the increase in temperature. Rods AB and EF are made of steel, and cach has a cross-sectional area of 125 mm. CD is made of aluminum and has a cross-sectional area of 375 mm. E = 200 GPa, Ea = 70 GPa, and au = 23(10)/C a7 mm ல் mm 300் m