Bat Vision
Classical Mechanics
Level
2
A bat finds its prey by using echolocation. It emits a very high frequency sound which reflects off the prey and reaches back to the bat. The bat then analyses this echo to find the relative distance and speed of the prey.
How does the bat find out the speed of the prey?
From the intensity of the echo
From the frequency of the echo
From the time taken for the echo to reach the bat
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
1 solution
The Bat uses Doppler Effect to detect the speed of its prey by observing the amount change in the frequency of the reflected sound with respect to the sound that the bat originally emitted .
This simply happens because speed of sound waves are dependant on the medium it travels through and the speed of the source. When it reflects from a moving body, the speed of the waves increase if the wave gets reflected from a incoming object. This consecutively increases the frequency of the reflected wave. The reverse happens if the wave reflects from an outgoing prey. Observing the shift in frequency, the bat understands the speed of the prey.