Answer to Question #105056 in Math for Riana Craft

Question

The huge volcanic eruption on the island of Krakatoa, Indonesia, in 1883 was heard on Rodrigues Island, 4,782 km (2,970 miles) away. How long did it take the sound to travel to Rodrigues? (Assume the air temperature is 20°C.)

Answer 1

The speed of sound (a) depends on the type of medium and the temperature of the medium:

$a = (Lambda×R×T)^{0.5},$

Lambda = ratio of specific heats (1.4 for air at STP),

R = gas constant (286 meters squared / second squared / degree Kelvin for air),

T = absolute temperature (273.15 + degrees centigrade).

At sea level, the speed of sound is about 761 miles per hour or 1,225 kilometers per hour.

The sound of the eruption would have traveled to Rodrigues Island in:

2,970/761 = 3.903 hours = 3 hours 54 minutes 10 seconds.