The Difference between Mass

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The Difference betweenMass Weight

• Thats heavy man. Heavy

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What we learned last time

• Gravity is dependant upon the mass of two objects
  and the distance between them.
• If mass increases Force of Gravity increases
• If distance increases Force of Gravity
  decreases.

Jupiter has more mass than Earth Therefore it
has more gravity
The satellite is farther from the center of Earth
than we are Therefore the planet is not pulling
as hard on the satellite as the person standing
on the surface!
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What is Weight?

• Definition Weight is a measurement of how
  strongly gravity pulls on a mass.
• Weight is completely dependent on the amount of
  gravity there is.
• It the result of the force of gravity!!!
• Without gravity there is NO WEIGHT (the ultimate
  diet plan!!!)

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What does weight depend on?

• The weight of an object depends on the objects
  mass.
• In fact, an objects weight is directly
  proportional to the objects mass.
• The weight of an object also depends on the
  objects location.
• In fact, an objects weight is directly
  proportional to its free fall acceleration, g at
  its current location.

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Amount of Mass Gravity Weight

• If you add more mass youve increased the
  attractive force between you and the earth
• Therefore you weigh more!

The Earth must really like me!
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Gravity, Distance and Weight

• If I leave the earth and head to outer space, I
  am farther away from the gravity source.
• Therefore, you weigh less.

Dude! I CAN FLOAT AROUND!
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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

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• Mass and Weight are different!
• ? Mass is an intrinsic property of an object. It
  is completely determined by the number and type
  of atoms that make up the object. It does not
  depend on the environment in which the object is
  located.
• ? But weight is different. Weight depends on both
  the object itself, and on some other object that
  exerts the gravitational force.

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Mass and Gravity Weight
Weight really is a measurement of the
gravitational attraction between you and the
earth. Remember Weight is a force measurement
When gravity pulls on your mass, the resulting
force is called weight!
Source of Gravity
Source of Gravity
Large mass more pull more weight
Small mass less pull less weight
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Compare Mass vs. Weight on different planets
Same person on Jupiter is 354.6 lbs!!!
Person on Earth is 150 lbs!
Why is this true? What is different between
Jupiter and Earth?
Jupiter has more mass than the Earth Therefore it
has more gravity! Your same mass would weigh
more on Jupiter than on Earth!
Q Did the persons MASS (amount of matter that
makes them up) ever change?
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Q How does gravity accelerate an object?
How objects fall as a result of gravity was a
matter of debate for scientific thinkers as far
back as ancient times!
A philosopher named Aristotle felt that heavier
objects (greater weight) would fall faster than
lighter objects when pulled by gravity This
idea was accepted for 100s of years!
After many years (during the renaissance) a
scientist named Galileo had a different idea
To try and prove his idea, he took cannon balls
to the top of the leaning tower of Pisa
And then he dropped them!!!
He felt that all objects would fall at the same
rate no matter what the mass or weight was
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Test of Gravity

• Which one fell faster the heavier one or the
  lighter 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
  Earths gravity?

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Acceleration Rate of the Earth
What is the acceleration of this interval?
What is the acceleration of this interval?
What is the acceleration of this interval?

• Gravitys Acceleration on the Earth 9.8 m/s2

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Wait a second!
We already talked about how 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?
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Q So what if we got rid of all the air?
Feather Drop in a Vacuum
Galileo Experiment Apollo 15 Hammer Feather
Experiment Google Video
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So how do we solve for weight?
Force Mass x Acceleration
Acceleration Rate of Earths Gravitational Pull
Weight Mass x Gravity Acceleration
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• Compare your weight on Earth to what is would be
  on the Moon
• Discuss Why does your weight change?
• Discuss Does your mass change as well?

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Changes in Mass???
1000kg
1N
Notice that the weight has increased but the mass
stays the same.
0kg
0N
Mass Weight
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Acceleration Force Review
Rate at which things move faster or slower

• Amount of matter (atoms) the object has.
• Has Inertia Resistance to change.

• Push or Pull
• Makes things with mass accelerate