A manufacturer studies how alloying affects the stiffness of an aluminium rod. Before alloying, the rod has a density of 2700 kg/m³ and the speed of longitudinal sound waves in it is measured to be 5100 m/s. After alloying, the density becomes 2900 kg/m³ and the measured speed is 4950 m/s.
Answer the following:
a. (i) Calculate the original Young’s modulus of the pure aluminium rod.
b. (ii) Calculate the Young’s modulus after alloying.
c. (iii) Find the percentage change in stiffness caused by alloying.