A 60.0-m-long brass rod is struck at one end. A person at the other end hears two sounds as a result of two longitudinal waves, one traveling in the metal rod and the other traveling in air. What is the time interval between the two sounds? (The speed of sound in air is 344 m/s; see Tables 11.1 and 12.1 for relevant information about brass.)

Table 11.1

Table 12.1

Approximate Elastic Moduli Young's Modulus, () Bulk Modulus, Shear Modulus, S (Pa) Material B (Pa) Aluminum 7.0 x 1010 7.5 x 1010 2.5 x 1010 Brass 9.0 x 10" 6.0 x 10" 3.5 x 1010 Copper 11 x 100 14 x 1010 4.4 x 1010 Iron 21 x 1010 16 x 1010 7.7 x 1010 Lead 1.6 x 1010 4.1 x 1010 0.6 x 1010 Nickel 21 x 1010 17 x 1010 7.8 x 1010 Silicone rubber 0.001 x 1010 0.2 x 1010 0.0002 x 100 Steel 20 x 1010 16 x 1010 7.5 x 1010 Tendon (typical) 0.12 x 1010 Densities of Some Common Substances Material Density (kg/m)* Material Density (kg/m)* Air (1 atm, 20C) 1.20 Iron, steel 7.8 x 103 Ethanol 0.81 x 103 Brass 8.6 x 103 Benzene 0.90 x 103 Copper 8.9 x 103 Ice 0.92 x 10 Silver 10.5 x 10 Water 1.00 x 103 Lead 11.3 103 Seawater 1.03 109 Mercury 13.6 x 103 Blood 1.06 x 10* Gold 19.3 x 10 Glycerine 1.26 x 103 Platinum 21.4 x 103 Concrete 2 x 103 White dwarf star 1010 Aluminum 2.7 x 103 Neutron star 1018