Question

A small boat on a lake explodes. Who will hear it first: the people on shore 725m away or a dolphin swimming 3km directly under the boat?

A) People on shore
B) Dolphin
C) Both at the same time
D) Cannot be determined

Answer 1

The dolphin will hear the sound of the explosion first because sound travels faster in water than in air.

Step-by-step explanation:

The speed of sound in different mediums determines how quickly the sound of the explosion reaches the two parties. Sound travels faster in water than in air. The speed of sound in water is approximately 1500 m/s, whereas in air it is about 343 m/s at sea level and at 20°C. Given that the dolphin is 3000 m (3 km) away from the source of the explosion underwater and the people on the shore are 725 m away in air, we can calculate the time it takes for sound to reach both.

Time for sound to reach dolphin: 3000 m / 1500 m/s = 2 seconds

Time for sound to reach people on shore: 725 m / 343 m/s = 2.11 seconds

Thus, the dolphin will hear the explosion first, making option B (Dolphin) the correct answer.