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

Four objects each with charge +2.0×10−7c are located at the corners of a square whose sides are 2.0 m long. part a what quantities can be determined using this information? check all that apply. the electric force on a charged object placed at the center of the square. the mass of each object. the total electric potential energy of the system consisting of the four charged objects. part b find the electric force on a charged object placed at the center of the square.