A cylindrical brass rod of length 1.20 m is clamped at its mid-point and made to…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A cylindrical brass rod of length 1.20 m is clamped at its mid-point and made to vibrate longitudinally. Using a stroboscope, the laboratory technician measures the speed of the longitudinal waves in the rod to be 3400 m/s. The density of brass is 8.5 g/cm³.
Answer the following:
(i) State the relation connecting the speed of longitudinal sound waves in a solid rod, its Young’s modulus and its density.
(ii) Using the above relation, calculate the Young’s modulus of the brass rod in SI units.
(iii) The accepted value of Young’s modulus for brass is about 9.0×10¹⁰ Pa. Compare your calculated value with this standard value and comment briefly on the agreement.