Weight and Mass

1
Weight and Mass

• Mrs. Wood
• 4th Grade

2
Index

• Definitions 3-4
• Newtons Second Law 5-6
• Weight 7-9
• Mass 10-14
• Examples 15
• YouTube Video 16
• MathCats 17
• Summary 18
• References 19
• Worksheet 20

3
Weight

• The force which is felt by a given mass due to
  gravity is defined as weight. The weight of an
  object on Earth, thus depends entirely on the
  gravity (force of attraction) that is between the
  object and Earth.

4
Mass

• Mass is the quantity of matter in an object.
• -its the stuff in stuff

5
Newtons Second Law

• The fundamental relation between the mass and the
  weight is defined by Newton's Second Law and can
  be expressed as
• F m a        
• where
• F force (N)
• m mass (kg)
• a acceleration (m/s2)

6
Newtons Law

• This equation helps us understand that if either
  of the mass increases, the increase in force of
  attraction will be directly proportional to the
  mass.

7
Weight

• Your weight depends on how much gravity is acting
  on you at the moment you'd weigh less on the
  moon than on Earth, and in interstellar space
  you'd weigh almost nothing at all.

8
Weight

• Wmg
• Weight mass x acceleration (due to gravity)

9
Weight

• Spring balance is used to calculate the weight of
  an object.

10
Mass

• Mass is often called as weight.
• Mass can be measured in both metric and customary
  units.
• Kilogram, gram, and milligram are the metric
  units whereas ounces and pounds are the customary
  units

11
Mass

• Scale is used to calculate the mass of an object

12
Mass

• Which object has more mass?
• a bowling ball or a tennis ball?
• a bicycle or a semi-truck?
• an egg or a chicken?
• If you were in outer space, which one of the
  above objects would have a greater mass?
• If you were in outer space, which one of the
  above objects would weight more?

13
Mass

• Which of the following metric units would you use
  to measure the weight of a pizza?Choices A.
  gramsB. millimetersC. secondsD. liters
• Correct Answer A
• Grams is used to measure not too small and not
  too large weights.

14
Mass

• Example
• -Suppose a sandwich weighs 7 ounces then the same
  mass in grams is approximately 200 grams.As 1
  ounce is about 28 grams then 7 ounce728 200
  grams.

15
Example

• Weight versus Mass
• A car's mass is 1,644 kg. The weight can be
  calculated
• w (1,644 kg)(9.807 m/s2)
•     16122.7 N
•     16.1 kN
• - there is a force (weight) of 16.1 kN between
  the car and the earth.

16
Mass vs. Weight Video

• YouTube Video

17
Math Cats

• Mass and Weight
• (click on above)

18
Summary

• So basically, the bottom line is that all objects
  have mass and weight. But, the difference between
  mass and weight is that mass remains constant no
  matter where the object is placed in the earth or
  in the universe. The weight will depend on the
  place where the object is placed.

19
References

• http//www.buzzle.com/articles/difference-between-
  mass-and-weight.html
• http//www.icoachmath.com/Sitemap/Mass.html
• http//www.engineeringtoolbox.com/mass-weight-d_58
  9.html
• http//www.mathcats.com/explore/balance/balance.ht
  ml

20
Worksheet

• Go to the assignment bin and get a worksheet on
  weight and mass
• Get into groups of two
• You have 20 minutes to complete the worksheet
  with your partner
• When completed, put the worksheet in the
  completed assignment bin