1. Newton’s 2nd
law of motion: An object
will accelerate in the direction of a force that
acts on it.
This explains gravity, because gravity is a
force that acts on everything- objects will
accelerate in the direction of gravity’s pull.
Otherwise known as, what goes up must
come down.
Objects accelerate towards earth at a rate of
9.8 m/s² due to the pull of gravity.
Force can be measured with this equation:
F= ma in newtons (N)
Newton’s are the measure of force. A Newton is
equal to (1kg • m/s²)
Gravity: the force that exists between any
two objects with mass, it is always attractive, (It’s a
very pretty force) and it pulls objects towards each
other.
Gravity is affected by two factors size and
distance. The larger an object the more
gravitational pull it has. Distance also affects

2. gravitational pull, the closer the object the more
gravity it has.
Circular motion and satellite motion:
Centripetal force is the type of force that creates
circular motion. Two forces working together to
create circular motion.
One force moving in a straight line and
another force pushing downward creates curved
motion. This is how satellites orbit a planet or
the sun. The horizontal motion is fast enough to
keep the downward force from pulling the
satellite down to the large object.
Air resistance is another force, when something falls
towards the ground the air it travels through pushes
against it. This creates an opposing force to the
motion. As the object accelerates because of gravity
the air resistance increases until it reaches a point
where the forces are balanced. When this happens
the object does not accelerate anymore. This is
called terminal velocity.
Center of mass is the point on the object that moves
as if all the mass is concentrated at that point. When
a stick or another object rotates in flight you can see
where the center of mass is.

3. Newton’s Third Law: For every action there is an
equal and opposite reaction.
This means that when a force acts on an object there
is a reaction that is equal in force in the other
direction.
Action/reaction forces don’t cancel each other out;
there is always motion of some kind.