4 in. 24 in. 1-in. diameter 20 in. 2.5 in. 12 in.

A weightlifting bar is loaded symmetrically in A and D (P = 1500N of each side). The weightlifter's hands are located at B and C, 0.45 m from A and D. Determine the maximum bending moment in the bar ABCD and the minimum diameter d of the bar knowing that the constraint admissible for the material of the bar is 200MPa.

The beam is made of four aluminium plates welded together as shown in Figure 1. Knowing that E = 65 GPa and neglecting the effect of the fillet. i. An engineer has been asked to change the material of the beam from aluminium to bronze, having ultimate normal stress 600 MPa, and E = 100 GPa. The design of the beam will remain as per Figure 1. Determine the maximum bending moment M that can be applied from which the factor of safety will be 2.5.