An atom is made of three basic subatomic particles: protons, neutrons, and electrons. which of these carry a charge?
a. proton and neutron
b. proton and electron
c. neutron and electron
d. proton, neutron and electron

In a closed system, the total energy prior to an energy transformation is the total energy after. a. equal to b. unrelated to c. greater than d. less than

What are two different ways you could find the value of a? explain these methods.

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