At stp conditions (

), the speed of sound is

The sound wave moves by uniform motion, so we can use the basic relationship between space, time and velocity:

where S is the distance covered by the sound wave in a time t. In our problem, t=3.00 s, therefore the distance covered by the sound wave is
D, I believe is the correct answer. Hope I answered your question, have a good day.<span />
Answer:
80kg = 133 Newtons I'm pretty sure this is right.
Copernicus's model states that the sun is in the center, and that the planets move around it in a circle. Kepler's first law of planetary motion says that they move around the sun in an ellipse.