Sound waves are generated by a rock falling into the sea. The sound waves travel through water and through air, traveling faster through water than through air. The figure shows a lifeguard and a swimmer. The lifeguard is on the beach, 20 meters away from where the rock lands, and the swimmer is underwater, 20 meters away from where the rock lands. Who would the first person to hear the splash made by the rock be, the lifeguard or the swimmer?
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1 point
The guy on the beach
The scuba diver
The swimmer.
The first person to hear the splash made by the rock would be the swimmer underwater, as sound waves travel faster through water than through air.
To determine who would be the first person to hear the splash made by the rock, we need to consider the speed of sound through water and air.
Sound travels faster through water than through air. In water, sound travels at approximately 1500 meters per second, while in air it travels at around 343 meters per second.
Since the swimmer is underwater and closer to where the rock lands, sound waves through water would reach them faster. The distance between the swimmer and the rock is 20 meters, and sound travels at 1500 meters per second through water.
To calculate the time it takes for sound to reach the swimmer:
Time = Distance / Speed
Time = 20 meters / 1500 meters per second
Time = 0.0133 seconds
On the other hand, the lifeguard is on the beach, 20 meters away from where the rock lands. The sound waves would have to travel through air, which is slower.
To calculate the time it takes for sound to reach the lifeguard:
Time = Distance / Speed
Time = 20 meters / 343 meters per second
Time = 0.0582 seconds
Comparing the two times, it is evident that the swimmer would be the first person to hear the splash made by the rock. Therefore, the answer is the swimmer.