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A bat, flying toward the east at 2.0 m/s, emits a shriek that is reflected back to it from a wall that is 20.0 m in front of the bat at the instant the shriek is emitted. Sound travels at 340 m/s in the air. How many milliseconds after emitting the shriek does the bat hear the reflected echo from the wall?

2 Answers

3 votes

Answer:


T = 116.9 ms

Step-by-step explanation:

As we know that bat emits the sound when it was at distance of 20.0 m from the wall

so the time taken by the sound to reach the wall is given as


t_1 = (20)/(340)


t_1 = 58.8 ms

Now in the same time distance moved by bat is


d_1 = v t


d_1 = 0.1176 m

now distance between bat and the wall is given as


d' = 20 - 0.1176 = 19.88 m

now since reflected sound and bat both moving towards each other so here time taken to reach the sound again on bat is given as


t_2 = (d')/(v + v_s)


t_2 = (19.88)/(340 + 2)


t_2 = 58.1 ms

so total time taken is given as


T = 58.1 + 58.8


T = 116.9 ms

User Andrew  Nexintong
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7.5k points
0 votes

Answer:

The bat hear the reflected echo after 117.6 s after emitting the shriek.

Step-by-step explanation:

Given:

  • Distance between the wall and the bat d=20 m
  • speed of sound in air v=340 m/s

It is given that the shriek is reflected back at the same instant it is emitted.

So the total distance travelled sound in air is 2d =40 m.

The time taken in reaching to the wall and coming back to the bat is same.

Let t be the time taken given by


t=(2d)/(v)\\t=(40)/(340)\\t=1.176\ \rm s\\t=117.6\ \rm milliseconds

User Daraan
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7.9k points