During the National Day this year, classmate Xiaoyun traveled to western Sichuan with her parents. Standing in the ravine between two picturesque mountains and admiring the beautiful scenery, she coul

During the National Day this year, classmate Xiaoyun traveled to western Sichuan with her parents. Standing in the ravine between two picturesque mountains and admiring the beautiful scenery, she couldn't help but feel

If the speed of sound is 340 meters per second, and the first mountain is A meters away from Xiaoyun, it should satisfy:

2(340-A) - 2A = 340m/ s x1s or A = 85m. The distance from another mountain is 340-85=255 meters.

The third echo should be the return of the second echo, and the fourth echo should be the return of the first echo. According to the above calculation, the distance traveled by the sound during the fourth echo is: 85x2+225x2 =340x2=680 meters. The required time is 680m/340m/s =2s.

1. The two mountains are 85 meters and 340-85=255 meters away from Xiaoyun respectively;

2. When Xiaoyun heard the fourth echo, he praised him. The time interval between beeps is 2s.