MASS, WEIGHT, AND GRAVITYWHAT IS MASS AGAIN? Since mass is a measurement of the amount of matter in...
Transcript of MASS, WEIGHT, AND GRAVITYWHAT IS MASS AGAIN? Since mass is a measurement of the amount of matter in...
WHAT IS MATTER?
Matter is what makes up every object
in our universe.
Atoms are the smallest whole units of
matter
All objects in the universe consist of
atoms
SO,WHAT IS MASS AGAIN?
Since mass is a measurement of the
amount of matter in an object, then:
AN OBJECT’S MASS DEPENDS ON TWO
THINGS:
1. The number of atoms that the object
contains/consists of
2. How massive (heavy, large) the atoms
in the object are.
Vince Wilfork has more mass.
He and Tom are made of the same kinds of atoms, but…
Vince is clearly larger than Tom, so…
Vince is made of more atoms than Tom, so he has more mass.
The block of metal has more mass.
Each is about the same size, but…
The metal block is made of heavier atoms, so…
Since its atoms are more massive, the block of metal has more mass.
The bowling ball has more mass.
Each is about the same size, but…
The bowling ball is solid, so…
it is made of more atoms than the “hollow”soccer ball, so it has more mass.
MASS IS MEASURED BY A TRIPLE BEAM BALANCE
ZEROING:
TO MOVE POINTER UP ABOVE THE
ZERO MARK, TURN THE THUMBSCREW
COUNTERCLOCKWISE (WHEN
FACING IT)
‘UP AND AWAY’
TO MOVE POINTER DOWN BELOW
THE ZERO MARK, TURN THE
THUMBSCREW CLOCKWISE (WHEN
FACING IT)
‘DOWN TO EARTH’
*MEASURING – MOVE LARGEST
MASS FIRST
TRICK QUESTION!
An astronaut is made of the same
types of atoms, and the same number
of atoms, both on earth and in space,
so the astronaut’s mass is the same in
both places!!!
An object’s WEIGHT depends
on its MASS and the strength
of the GRAVITY pulling on it:
GRAVITY is the attractive force between 2 objects.
ALL OBJECTS with mass have a force of gravity: is
dependant upon the mass of two objects and the
distance between Jupiter has
more mass
than Earth;
Therefore
it has more
gravity
An object’s WEIGHT depends
on its MASS and the strength
of the GRAVITY pulling on it:
On which planet would you have a GREATER
WEIGHT???is dependant upon the mass of two objects
and the distance between
Jupiter has
more mass
than Earth;
Therefore
it has more
gravity
Weight depends on MASS
AND GRAVITY:
The force of gravity between two objects is
dependent upon the mass of two objects and the
distance between them.
If the distance between the objects increases – the Force
of Gravity decreases.
The astronaut is farther from the center of
Earth than we are;
Therefore the planet is not pulling as hard
on the astronaut
as the person standing on the surface!
Weight depends on MASS
AND GRAVITY:
If the distance between the objects
increases – the Force of Gravity decreases.
Where would you WEIGH MORE: On Earth
or in space?
The astronaut is farther from the center of
Earth than we are;
Therefore the planet is not pulling as hard
on the astronaut
as the person standing on the surface!
So,What is Weight again?
Definition: Weight is the force of one object pressing on another.
Weight is dependent not only on an object’s mass, but also on the strength of the gravity that is pulling on it.
Without gravity there is NO WEIGHT
Mass ≠ Weight
Mass and Weight are NOT the same thing!
Mass: Amount of matter an object contains
Has inertia (resistance to a push/pull)
Weight (Force):
Dependant upon Gravity (mass is not)
Attraction between two objects
Can change if the objects change distance
or mass
When gravity pulls on
your mass,
the resulting force is
called “weight”!
Mass and Gravity = Weight
Small mass x same
pull = less weight Large mass x same pull =
more weight
Source of Gravity Source of Gravity
Weight really is a measurement of the gravitational
attraction between you and the earth.
Remember – Weight is a force measurement
Compare: Mass vs. Weight on
different planets:
Jupiter has more mass than the Earth
Therefore it has more gravity! Your same
mass would weigh more on Jupiter than on Earth!
Person on Earth
is 150 lbs!
Same person on
Jupiter is 354.6 lbs!!!
Why is this true? What is different
between Jupiter and Earth?
Q: Did the person’s MASS (amount
of matter that makes them
up) ever change?
Test of Gravity
Drop a paperclip and a pen at the
same time, from the same distance.
Observe which one fell faster – the
more massive or the less massive
one?
Galileo found that no matter how
large or small, the objects fell at
the same Velocity.
So at what rate do objects accelerate
due to Earth’s gravity?
Test of Gravity
Which one fell faster – the
more massive or the less
massive one?
Galileo found that no matter
how large or small, the
objects fell at the same
Velocity.
So at what rate do objects of
different masses accelerate
(fall) due to Earth’s gravity?
Wait a second!
Leaves and feathers
fall very slowly and even changes directions
So what makes the leaf and feather fall
differently than a cannon ball?
So will feathers and leaves always
fall slower than cannon balls?
Force = Mass x Acceleration
So how do we solve for
weight?
Ns
mkg
s
mgravityofrateonAcceleratikgmassNForce
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Weight = Mass x Gravity
Acceleration
Acceleration Rate of Earth’s
Gravitational Pull