A penny is made of the element zinc plated with the element copper; a nickel is made of a mixture of the elements nickel and copper. Some isotopes of various elements are listed below by their atomic number and mass number. Use the periodic table on p. 131 to identify which atoms you would expect to find in the penny, which you would expect to find in the nickel, which you would expect to find in both, and which you would expect to find in neither coin.

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.

What is a good example of instantaneous speed

Directions: count the number of atoms. ar co2 na3po4 so3 nac2h3o2