Why does heat cause a substance to expand?

i. heat causes the substance's atoms or molecules to move faster.
ii. the substance gets larger because it converts heat to mass.
iii. heat drives water into the spaces between atoms or molecules.

Oxygen and nutrients are moved through the body by the: a. circulatory system c. lymphatic system b. digestive system d. reproductive system

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?

Most of the volume of an atom is occupied by the