Alarge boulder falls from a cliff located 1,044 meters away from a herd of elephants. the temperature of the air is 29°c. how long after the boulder crashes will the elephants hear the sound? a. 319 m/s b. 331 m/s c. 343 m/s d. 219 m/s

Two identical stars with mass m orbit around their center of mass. each orbit is circular and has radius r, so that the two stars are always on opposite sides of the circle. (a) find the gravitational force of one star on the other. (b) find the orbital speed of each star and the period of the orbit. (c) how much energy would be required to separate the two stars to infinity?