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Weight and MassWeight and Mass
Mrs. WoodMrs. Wood
44thth Grade Grade
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IndexIndex Definitions – 3-4Definitions – 3-4 Newton’s Second Law – 5-6Newton’s Second Law – 5-6 Weight – 7-9Weight – 7-9 Mass – 10-14Mass – 10-14 Examples – 15Examples – 15 YouTube Video – 16YouTube Video – 16 MathCats – 17MathCats – 17 Summary – 18Summary – 18 References – 19 References – 19 Worksheet – 20Worksheet – 20
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WeightWeight
The force which is felt by a given The force which is felt by a given mass due to gravity is defined as mass due to gravity is defined as weight. The weight of an object on weight. The weight of an object on Earth, thus depends entirely on the Earth, thus depends entirely on the gravity (force of attraction) that is gravity (force of attraction) that is between the object and Earth.between the object and Earth.
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MassMass
Mass is the quantity of matter in an Mass is the quantity of matter in an object. object.
-it’s the “stuff in stuff”-it’s the “stuff in stuff”
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Newton’s Second LawNewton’s Second Law
The fundamental relation between The fundamental relation between the mass and the weight is defined the mass and the weight is defined by Newton's Second Law and can be by Newton's Second Law and can be expressed asexpressed as
F = m a F = m a ~where~where
F = force (N)F = force (N) m = mass (kg)m = mass (kg) a = acceleration (m/s2)a = acceleration (m/s2)
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Newton’s LawNewton’s Law
This equation helps us understand This equation helps us understand that if either of the mass increases, that if either of the mass increases, the increase in force of attraction will the increase in force of attraction will be directly proportional to the mass. be directly proportional to the mass.
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WeightWeight
Your weight depends on how much Your weight depends on how much gravity is acting on you at the gravity is acting on you at the moment; you'd weigh less on the moment; you'd weigh less on the moon than on Earth, and in moon than on Earth, and in interstellar space you'd weigh almost interstellar space you'd weigh almost nothing at all. nothing at all.
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WeightWeight
W=mgW=mg Weight = mass x acceleration (due Weight = mass x acceleration (due
to gravity)to gravity)
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WeightWeight
Spring balance is used to calculate Spring balance is used to calculate the weight of an object.the weight of an object.
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MassMass
Mass is often called as weight. Mass is often called as weight. Mass can be measured in both metric Mass can be measured in both metric
and customary units. and customary units. Kilogram, gram, and milligram are Kilogram, gram, and milligram are
the metric units whereas ounces and the metric units whereas ounces and pounds are the customary units pounds are the customary units
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MassMass
Scale is used to calculate the mass of Scale is used to calculate the mass of an objectan object
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MassMass
Which object has more mass?Which object has more mass?
a bowling ball or a tennis ball?a bowling ball or a tennis ball? a bicycle or a semi-truck?a bicycle or a semi-truck?
an egg or a chicken?an egg or a chicken? If you were in outer space, which one of If you were in outer space, which one of
the above objects would have a greater the above objects would have a greater mass?mass?
If you were in outer space, which one of If you were in outer space, which one of the above objects would weight more?the above objects would weight more?
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MassMass Which of the following metric units would Which of the following metric units would
you use to measure the weight of a pizza?you use to measure the weight of a pizza?Choices: Choices: A. gramsA. gramsB. millimetersB. millimetersC. secondsC. secondsD. liters D. liters
Correct Answer: ACorrect Answer: A Grams is used to measure not too small and Grams is used to measure not too small and
not too large weights. not too large weights.
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MassMass
ExampleExample
-Suppose a sandwich weighs 7 ounces -Suppose a sandwich weighs 7 ounces then the same mass in grams is then the same mass in grams is approximately 200 grams.approximately 200 grams.As 1 ounce is about 28 grams then 7 As 1 ounce is about 28 grams then 7 ounce=7×28 200 grams. ounce=7×28 200 grams.
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ExampleExample
Weight versus MassWeight versus Mass A car's mass is A car's mass is 1,644 kg1,644 kg. The weight . The weight
can be calculated:can be calculated: w = (1,644 kg)(9.807 m/s2) w = (1,644 kg)(9.807 m/s2) = 16122.7 N = 16122.7 N = = 16.116.1 kN kN - there is a force (weight) of - there is a force (weight) of 16.1 kN16.1 kN
between the car and the earth.between the car and the earth.
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Mass vs. Weight VideoMass vs. Weight Video
YouTubeYouTube Video Video
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Math CatsMath Cats
Mass and WeightMass and Weight(click on above)(click on above)
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SummarySummary
So basically, the bottom line is that So basically, the bottom line is that all objects have mass and weight. all objects have mass and weight. But, the difference between mass But, the difference between mass and weight is that mass remains and weight is that mass remains constant no matter where the object constant no matter where the object is placed in the earth or in the is placed in the earth or in the universe. The weight will depend on universe. The weight will depend on the place where the object is placed. the place where the object is placed.
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ReferencesReferences
http://www.buzzle.com/articles/http://www.buzzle.com/articles/difference-between-mass-and-difference-between-mass-and-weight.htmlweight.html
http://www.icoachmath.com/http://www.icoachmath.com/Sitemap/Mass.htmlSitemap/Mass.html
http://www.engineeringtoolbox.com/mass-weight-d_589.html
http://www.mathcats.com/explore/balance/balance.html
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WorksheetWorksheet
Go to the assignment bin and get a Go to the assignment bin and get a worksheet on weight and massworksheet on weight and mass
Get into groups of twoGet into groups of two You have 20 minutes to complete the You have 20 minutes to complete the
worksheet with your partnerworksheet with your partner When completed, put the worksheet When completed, put the worksheet
in the completed assignment binin the completed assignment bin
