In most cases, what happens to a liquid when it cools?
a) its density increases
b) its density decreases
c) its mass increases
d) its mass decreases
e) its volume increases
f) its volume decreases

10 newton object is placed 3 meters from the fulcrum. at what distance on the other side would you need to place a 15 newton object to balance the lever? show your work!

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?

The strong nuclear force acts over a small distance than the electrostatic force. true or false