**Physics in
a Nutshell**

__Acceleration__ = a change in speed: Speeding up…Slowing down… or changing
direction.

__Centripetal Force__ = The push or pull on a
moving object toward the center of its curved path. Centripetal force is a net
force.

__Force__ = A
push or pull that one object exerts on another object.

__Gyroscopic Inertia__ = "*A body that is set spinning has a tendency to
keep spinning in its original orientation." *For example, a top or
gyroscope will not fall over when it is spinning.

__Kinetic energy__ = The energy of a moving body. Kinetic energy = 1/2mv^{2}.

__Law of Conservation of Momentum__ = *"In a system consisting of bodies on which no
outside forces are acting; the total momentum of the system remains the
same."*

Momentum can be transferred from one object to another.

In an interaction, the momentum lost by one mass equals the
momentum gained by the other.

Total Momentum before interaction = The Total Momentum after.

A __net force__ is the sum of all forces acting
on an object. A net force is capable of accelerating a mass. For instance, if
the wheels of a car push it forward with 5 Newtons and
drag is 3 Newtons, the net force is 2 Newtons, forward. Motion to the right is positive. Motion
to the left is negative.

Newton's First Law of Motion (Law
of Inertia) =*"Every object remains in a state of rest
or of uniform motion in a straight line unless acted upon by an outside (net) force."*

Objects at rest remain at rest.

Objects in motion remain in motion in a straight line (unless
acted upon by an outside force.)

Things keep doing what they were doing until interrupted!

__Newton's Second Law of Motion (Force _{net} =
mass x acceleration) (F_{net} = ma)__

"*When
a force acts upon a body it accelerates that body in the direction of the
force. The acceleration produced is directly proportional to the force and
inversely proportional to the mass of the body."*

Objects move in the direction they are pushed or pulled.

It is easy to push or pull lighter masses.

It is harder to move larger masses.

Things accelerate more quickly when a greater force is used.

Newton's Third Law of
Motion = *"For every action or force there is an
equal and opposite reaction or force."*

Any time you touch an object, it is touching you with the same
amount of force. **Forces
always come in equal and opposite pairs.** This means that the forces are equal even when a big object
crashes into a small object.

Force = - Force

mass x acceleration = - mass x acceleration

__Newton's Law of Gravitation (Inverse Square Law) __= "*Any two bodies in the universe
attract each other with a force that is directly proportional to their masses
and inversely proportional to the square of their distance apart. (If the
distance between 2 objects is doubled, the force of gravity falls to 1/4 of its
former value.)"*

Gravity depends on the mass of objects and the distance between
them!

__Potential energy__ = Energy that is stored. Energy of
position or state. Gravitational PE = mgh. PE
of a rubber band = 1/2kx^{2}

__Rotational Inertia__ = the property of an object that resists any change in its
state of rotation. If at rest, it tends to remain at rest; if rotating, it
tends to remain rotating and will continue to do so unless interrupted. For
example, think of a metal ring and a solid disk, each with the same mass. The
metal ring has its mass at the perimeter and therefore has more rotational
inertia than the solid disk. Thus, the ring resists rolling from a state of
rest.

Speed =
Distance/Time

Velocity
= Speed and direction