Vertical link 2 is rigidly fixed to the ground (at A) and pinned to horizontal link 3 at B. Link 4 is pinned to link 3 at H, and the mass of link 4 is 200 kg. Vertical link 5 is pinned to link 3 at D and to the ground at O5. Link 2 has a solid circular cross section with diameter d2 =

25 mm, compressive yield strength Syc = 370 MPa, and modulus of elasticity E = 205 GPa.

The factor of safety guarding against buckling, for link 2, is N = 2.5, and the end-condition constant C = 2. Assume that gravity is acting vertically downward, and links 2, 3, and 5 are massless compared to link 4.

(a) For link 2 determine: (1)

the slenderness ratio; and (2) the slenderness ratio at the point of tangency between the Euler column formula and the Johnson parabolic formula. (b)

Determine the critical unit load acting on link 2.

(c) If the diameter of link 2 is increased to d2 = 90 mm, then is link 2 an Euler column or a Johnson column?