Gravity always acts downward on every object on earth. Gravity multiplied by the object's mass produces a force called weight. Although the force of an object's weight acts downward on every particle of the object, it is usually considered to act as a single force through its balance point, or center of gravity.
Answer:
second and last are true
Step-by-step explanation:
This could be a situation in which items are both bought and sold. In calculating the inventory, positive numbers represent items bought, negative numbers represent items sold and 0 would be no items in the inventory.
Another type of situation would be the displacement of an object from the original position. Where 0 would represent the original/starting position, positive values would represent distance moved forward, negative values represent distance moved backwards.