The first dancer in the line is 10 m from the speaker playing the music; the last dancer in the line is 120 m from the speaker. Approximately how much time elapses between when the sound reaches the nearest dancer and when it reaches the farthest dancer

0.321 seconds

Explanation:

Let assume that air has a temperature of 20 °C. Sound speed at given temperature is . As sound spreads at constant speed, time can be easily found by using this formula:

the device is called “ rocket engine”

the force on the thing and the distance the force moves the thing