Magnetic fields are produced by: (a) atoms (b) currents (c) voltages (d) charges

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

The long handle on a rake is a(n) a. lever b. screw c. wedge d. inclined plane

The three classes of rocks are sedimentary, metamorphic, and igneous. how are rocks classified into one of these three groups?