gravity the acceleration due to gravity on earth is 9.8 m/sec 2 (~22 mph/sec) (this means that each...
TRANSCRIPT
GRAVITY
GRAVITY GRAVITY
GRAVITY
•The acceleration due to gravity on Earth is
9.8 m/sec2 (~22 mph/sec)
(This means that each second an object falls, it increases its speed by 9.8 m/sec until itreaches its terminal velocity)
•a force of acceleration that causes objects to become attracted to each other
-based on the object’s mass and distance between them
•Gravity pulls all objects at the same rate.
•Mass does not affect the pull from gravity.
•Weight: How heavy an object is because of gravitational pull
•Mass: Amount of matter in an object
However….
Some objects do fall slower because of
AIR RESISTANCE
-A force that opposes the motion of an object as it moves through air
•highest speed that an object can fall at determined by the object’s shape and mass
Once an object reaches its terminal velocity,it falls at a constant velocity.
(It does not accelerate unless its shape changes.)
TERMINAL VELOCITY
Some objects also fall slower because of their……
Reaches this when the air resistance exerts an upward force exactly equal and opposite to the force of gravity. Heavier mass needs faster falling speed for drag to equal gravity
The elephant hits first because of its mass. It takes more time to reach its terminal velocity.
The feather reaches its terminal velocity very quickly because it has very little mass.
Vacuum: A vacuum is a place that has no matter – thus there is no air (ex: in outer space)
All objects will fall at the same velocityregardless of shape and mass.
If there is no air, there is no air resistance
Tennis ball test
…..but with air resistance and outside factors, the speed should be between 40-50 mph.
A tennis ball’s terminal velocity is about 70 mph.
Other Terminal VelocitiesHuman ~120mphRaindrop ~ 12mph16lb Bowling Ball ~ 163mphBaseball ~ 75mph
HOW WOULD OUR LIVES BE DIFFERENT WITHOUT GRAVITY???
http://www.explorelearning.com/
Sign up for the gravity interactive – off the leaning tower of pisa
Teacherdomain.org
Balloon Car Project due Friday
Poster
Data Tables (re-done on the computer)•Distance•Top Speed•Momentum
Builders Journal (preferred typed)
Terms Sheet (typed)
UPCOMING SCIENCE EVENTS
Mini Project Next Week
Test on Thursday 22nd 1st or 2nd Week in January
Science Placement Test from PV
LET’S REVIEW………..NEWTON’S LAWS
AN OBJECT IN MOTION WILL STAY IN MOTION UNLESS ANOTHER FORCE STOPS IT
AN OBJECT AT REST WILL STAY AT REST UNLESS ANOTHER FORCE STARTS IT
FIRST LAW
SECOND LAW
FORCE = MASS x ACCELERATION
“HEAVIER OBJECTS NEED MORE FORCE TO GET THEM GOING OR TO STOP THEM”
THIRD LAW
EVERY ACTION HAS AN EQUAL AND OPPOSITE REACTION
AIR GOES THIS WAY
CAR GOES THIS WAY
IT WILL NOT MOVE UNTIL YOU GIVE IT A FORCE-IT WON’T STOP UNTIL FRICTION OR A WALL STOPS IT.
YOUR BALLOON CAR WILL EXPERIENCE ALL THREE
THE HEAVIER YOUR CAR IS, THE MORE FORCE IT WILL TAKE TO GET IT GOING
WHEN THE AIR COMES OUT OF THE BALLOON, YOUR CAR WILL GO FORWARD (the opposite way)
