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ORBITAL MOTION
Inertia, Gravity, and
Weightlessness
Inertia
Newton’s 1st law of MotionObjects in motion will remain in motion, objects at
rest will remain at rest unless acted upon by an
outside force. (CRASH TESTS)
Inertia - The tendency of objects to resist a change in
motion. (Texas Native Inertia Nut Cracker)
Forces don’t keep objects moving INERTIA does
FORCE
A FORCE is a push or a pull.
Forces act on bodies in 2 ways…
Contact ForcesPhysical Contact is needed to create push or pull.
Examples: Applied Force, Tensional Forces
Distance ForcesNO physical contact is needed to create force.
Examples: Gravitational Forces, E-M Forces
A Universal FORCE
Gravity = The force of attraction between
all objects in the universe (Newton's Law
of Universal Gravity).
Strength of GRAVITY
Gravitational Strength is
due to…
MASS
DISTANCE
The force of gravity increases as the mass of the objects increase. (Direct Proportion)
Gravity decreases as the distance between two objects increase. (Indirect Proportion).
FREE FALLING – NOW I’m Free
Falling
All objects,
no matter
their mass,
fall to Earth
at a rate of
9.8 m/s²
HOWEVER,
Air resistance
can cause
some objects
to reach their
terminal
velocity.
FREE FALL ON
THE MOON
MASS = WEIGHT
Mass is the amount of matter in an object.
Weight is due to
your mass and
the acceleration
due to gravity.
“g” = 9.8m/sec.²
Weightlessness
Zero g
A sensation experienced by an individual when there are no contact forces acting on that individual.
An example is
when in a state
of free-fall.
Gravity and Inertia CREATE sensation of Weightlessness
ORBITAL MOTION
A result of the combination of an objects
forward inertia and the downward pull of
gravity.
ORBITING SATELLITES
•Since Earth is CURVED,
objects with enough
inertia will stay in a
state of freefall, orbiting
Earth, creating the
sensation of
weightlessness.
