Question

On a 20∘C night, a bat hovering in the air emits an ultrasonic chirp that has a frequency of 45 kHz. It hears an echo 58 ms later:

How far away is the object that reflected the ultrasound?

Answer 1

The object that reflected the ultrasound is approximately 10 meters away from the bat, using the speed of sound at 20°C and the echo time.

Step-by-step explanation:

To calculate how far away an object is that reflected the ultrasound, we can use the speed of sound in air and the time it takes for the echo to return to the bat. The speed of sound in air at 20°C is approximately 343 meters per second (m/s). The echo is heard after 58 milliseconds (ms), which is 0.058 seconds. Since sound has to travel to the object and back, we divide the total time by 2 to find the time for one-way travel. Thus, the distance to the object is:

Distance = speed of sound × time/2

Distance = 343 m/s × 0.058 s / 2

Distance = 9.947 m, which we can round to 10 meters.

Therefore, the object that reflected the ultrasound is approximately 10 meters away from the bat.