Apple Interview Question: What is the difference in den... | Glassdoor

Interview Question

Product Design Engineer Interview Cupertino, CA

What is the difference in density between Aluminum and

  Steel? What is the difference in Modulus of Elasticity between Aluminum and Steel?

Interview Answer

2 Answers


Steel has higher density and a higher Modulus of Elasticity (greater slope on a stress-strain curve)

Ryan on Sep 4, 2017

The density of Aluminum is about 2700 kg/m^3 and the density of steel is about 8050 kg/m^3 which means that for the same volume of material, the aluminum piece will be about 3X less massive. The modulus of elasticity of Aluminum is about 69GPa and steel's is about 180-200GPa depending on the alloy and the treatment (annealing, hardening). Steel is more stiff than Aluminum, meaning that for the same cross section of a beam, a steel beam would bend about 3X less.

Anonymous on Nov 14, 2017

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