Question

How long would it take for a sound impulse to travel through an aluminum rod 25 kilometers long? A. 0.0049 sec B. 0.071 sec C. 4.9 sec D. 0.14 sec

Answer 1

Answer: The answer is C. 4.9 sec.

Explanation:

Answer 2

Answer:

c) 4.9 s

Explanation:

Young's modulus of aluminium is given as

$Y = 69 \times 10^9 pa$

density of aluminium is given as

$\rho = 2700 kg/m^3$

now the speed of sound in aluminium is given as

$v = \sqrt{\frac{Y}{\rho}}$

$v = \sqrt{\frac{69 \times 10^9}{2700}}$

$v = 5055.3 m/s$

now the time taken by the sound to travel a distance of d = 25 km

$t = \frac{d}{v}$

$t = \frac{25 \times 10^3}{5055.3}$

$t = 4.9 s$