Suppose that a heavy person and a light person are balanced on a teeter -totter made of plank of wood .Each person now moves in toward the fulcrum the distance of 25 cm. What effect will this have on the balance of the teeter-totter? The light person's end will go down. The heavy person's end will go down, The teeter-totter will remain in balance. One cannot tell whether either end will rise or fall without knowing the relative mass of the plank. Only if the plank has significant mass will the light person's end go down.
