What is the difference between injection moulding a polymer product, vs vacuum forming a polymer product? If you were handed a plastic container and asked to tell if it was vacuum formed, what features would you look for? $(5)($b$)$ Copper pipes could be made by rolling, or extrusion. Explain the difference between the rolling and extrusion processes. What feature would you look for to indicate a pipe or tube was rolled? $(5)($c$)$ The races $($rings$)$ of rolling element bearings are typically forged and rolled to approximate initial shape and size, before final dimensions are achieved by turning, grinding and polishing. Why are forming processes preferred to casting processes for the initial shape?