You drop a rock down a well that is 31 m deep. How long does it take the rock to hit the bottom of the well?
A. 1.9 s
B. 2.7 s
C. 6.3 s
D. 2.5 s

Alarge box of mass m is pulled across a horizontal frictionless surface by a horizontal rope with tension t. a small box of mass m sits on top of the large box. the coefficients of static and

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)

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?