What is a difference between a law and a hypothesis?

a. a law describes how two variables affect each other, but a hypothesis only discusses one variable.
b. a law must be testable so that it can be proven, but a hypothesis is an untestable explanation.
c. a hypothesis includes an explanation for why two variables affect each other, but a law only describes how they affect each other.
d. a hypothesis may or may not be testable, but a law is an untestable explanation of why two variables affect each other and cannot be proven.

Amerry-go-round of radius r, shown in the figure, is rotating at constant angular speed. the friction in its bearings is so small that it can be ignored. a sandbag of mass m is dropped onto the merry-go-round, at a position designated by r. the sandbag does not slip or roll upon contact with the merry-go-round. how would you rank the following different combinations of m and r on the basis of the angular speed of the merry-go-round after the sandbag "sticks" to the merry-go-round from largest to smallest. a) m = 10kg, r = 0.25r b) m = 20kg, r = 0.25r c) m = 10kg, r = 0.50r d) m = 10kg, r = 1.0r e) m = 15kg, r = 0.75r f) m = 40kg, r = 0.25r