In this problem, consider the following potential materials: $304$ stainless steel, $6061$ aluminum, titanium, brass, copper, lead, concrete, acrylic, rubber, porcelain, granite, marble, oak, pine, balsa, cotton, nylon, silk, kevlar, carbon$-$fiber composites, diamond, and graphene. $($For some materials like cotton and nylon, you may need to search for values when formed in a rope.

Stiffness$-$to$-$weight is a common design variable. Look up Young$$s modulus E and density $\backslash$rho for these materials and rank them in order of decreasing E$/\backslash$rho $.$ Can you draw any conclusions from this list?

Strength$-$to$-$weight is a common design variable. Look up ultimate tensile strength $\backslash$sigma u and density $\backslash$rho for these materials and rank them in order of decreasing $\backslash$sigma u$/\backslash$rho $.$ Can you draw any conclusions from this list?