Weightlessness and Orbital Motion
32
WEIGHTLESSNESS AND ORBITAL MOTION © Simon Porter 2007
Transcript of Weightlessness and Orbital Motion
WEIGHTLESSNESS AND ORBITAL MOTION
© Simon Porter 2007
CONCLUSION QUESTIONS 1-5
CONCLUSION QUESTIONS 6-10
WEIGHTLESSNESS
Weightlessness – free from the effects of gravity (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
ELEVATOR FUN!
WEIGHTLESSNESS
So there is a force of gravity on the astronaut, but no reaction
force from the floor so the astronaut feels weightless.
© Simon Porter 2007
YouTube
- flying
dog
YouTube
- Greg
Olsen -
Drinking
water on
the ISS
YouTube -
Zero G
Puke Bag
DRINKING WATER – ISS (GREG OLSEN)
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.
KEEPING THE WORLD SAFE FROM
MR. HASTINGS DOG!
From a table, medium kick.
HOW FAR CAN YOU KICK A DOG?
Gravity
HARDER KICK?
HARDER KICK
Gravity
SMALL CANNON?
Woof! (help)
SMALL CANNON
Gravity
Woof! (help)
BIGGER CANNON?
BIGGER CANNON
Gravity
Gravity
EVEN BIGGER CANNON?
EVEN BIGGER CANNON
GravityGravity
Gravity
VERY BIG CANNON?
VERY BIG CANNON
Gravity
HUMUNGOUS CANNON?
DOG IN ORBIT!
The dog is now in orbit! (assuming no air resistance of course)
DOG IN ORBIT!
The dog is falling towards the earth, but never gets there!
DOGS IN ORBIT!
The force that keeps an object moving in a circle is called the centripetal force (here provided by gravity)
Gravity
Inertia and gravity combine to keep Earth in orbit around the sun and the moon in orbit around the Earth.
A combination of gravity and inertia keeps the moon in orbit around the Earth.
WHY DO EARTH AND THE MOON REMAIN IN THEIR ORBITS?
If there were no gravity, inertia would cause the moon to travel in a straight line. If only gravity existed, the earth would be pulled into the sun.
DESCRIBE WHY AN ASTRONAUT WOULD
FEEL WEIGHTLESS.
DRAW A DIAGRAM OF EARTH ORBITING
THE SUN (LABEL FORCE ARROWS)
