Link AB is to be made of a steel for which the ultimate normal stress is 450 MPa. Determine the cross-sectional area for AB for which the factor of safety will be 3.50. Assume that the link will be adequately reinforced around the pins at A and B.

Complete Question

The complete question is shown on the first uploaded image

The cross-sectional area is

Explanation:

The free body diagram of the link is shown on the second  uploaded image

From the question we are told that

       Ultimate normal stress in the link

       Factor safety

From our free diagram we can see that the moment about B is 0 Mathematically

       But    

 Hence  

Making the  subject

 At equilibrium summation of all force is 0 mathematically

          This means

i.e        

The factor of safety is mathematically

                      Factor of safety

Where is the normal stress

            is the allowable stress this mathematically given as

Making A the subject

r = ρ x length / area  

ρ = r x area / length  

ρ is in ohm-meters  

in basic units, it is m³kg/s³a²  

i think this is it.