Which best describes the definition for the atomic mass of an element? It is a ratio based on the mass of the carbon 12 atom.

It is the sum of the protons and neutrons in one atom of the element.

It is twice the number of protons in one atom of the element.

It is a weighted average of the masses of an element's isotopes.

Awind turbine is rotating counterclockwise at 0.5 rev/s and slows to a stop in 10 s. its blades are 20 m in length. (a) what is the angular acceleration of the turbine? (b) what is the centripetal acceleration of the tip of the blades at t=0s? (c) what is the magnitude and direction of the total linear acceleration of the tip of the blades at t=0s?