Why do some objects fall through the air at a different rate then others (this is for science)

In most resting cells, the concentration of sodium ions is higher outside of cells compared with the intracellular fluid. when cells are stimulated, sodium ion channels open, and sodium diffuses from the outside of the cell to the inside of the cell. sodium ion concentrations in a resting cell are an example of and sodium ion movement in a stimulated cell is an example of in most resting cells, the concentration of sodium ions is higher outside of cells compared with the intracellular fluid. when cells are stimulated, sodium ion channels open, and sodium diffuses from the outside of the cell to the inside of the cell. sodium ion concentrations in a resting cell are an example of and sodium ion movement in a stimulated cell is an example of potential energy; kinetic energy kinetic energy; potential energy the energy of motion; stored energy chemical work; energy stored in chemical bonds