You are adjusting the tension in a stretched copper wire so that the velocity ratio of longitudinal waves to transverse waves is equal to 5. The cross-sectional area of the copper wire is 1 mm2 and the Young modulus of copper is 1 × 1011 Pa. Find the tensile stress (σ) in the wire.
An online tune generator creates sine sound waves in the air with a displacement amplitude of 0.04 mm at f1 = 200 Hz and f2 = 20 kHz. What is the pressure amplitude (pmax) at each frequency? Specify, under these conditions, if these sound frequencies are harmful to human hearing. The pressure variation that corresponds to the harm threshold is 30 Pa.