The Sun acts on Earth by a force of
magnitude 3.5 times 10 to the 22 newtons. What is the magnitude of the force
with which Earth acts on the Sun?
We can answer this question by
simply recalling Newton’s third law of motion. Newton’s third law states that
interacting objects exert equal and opposite forces on each other. In other words, when a force is
applied to an object, the object exerts an equal-sized force in the opposite
direction to the applied force. This is Newton’s third law, and
it’s important to remember that this applies to interactions between a pair of
objects, such as the Earth and Sun.
We can draw a diagram to help
illustrate this. The Earth and Sun are
gravitationally attracted to each other. The Sun attracts the Earth, and the
Earth attracts the Sun. Because of Newton’s third law, we
know that these forces act in opposite directions and that they have equal
So since the Sun acts on Earth by a
force of magnitude 3.5 times 10 to the 22 newtons, we know that Earth also acts on
the Sun by a force of magnitude 3.5 times 10 to the 22 newtons.