Chapter 5 Matter In Motion

1
Chapter 5 Matter In Motion

• Section 4 Gravity A Force of Attraction
• pp. 134 - 139

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IMPORTANT DEFINITIONS

• Gravity a force of attraction between objects
  that is due to their masses.
• Weight a measure of the gravitational force
  exerted on an object
• Mass the amount of matter in an object.

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MASS AND WEIGHT

• Mass and Weight ARE NOT the same thing!

WEIGHT
MASS
4
MASS VS. WEIGHT

• Mass
• Expressed in grams or kilograms
• Does not change no matter where you are
• Measured using a triple beam balance or an
  electronic balance
• Amount of matter in an object

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MASS VS. WEIGHT

• Weight
• Expressed in Newtons
• Measure of gravitational force on an object
• 6 times less on the moon than on Earth
• Changes when gravitational force changes
• Measured by using a Spring scale

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NEWTONS LAW OF UNIVERSAL GRAVITATION

• All objects in the universe attract each other
  through gravitational force. The size of the
  force depends on
• The masses of the objects
• The distance between the objects

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NEWTONS LAW OF UNIVERSAL GRAVITATION

• Gravitational force
• increases as
• mass increases.

• Gravitational force decreases as mass decreases.

8
NEWTONS LAW OF UNIVERSAL GRAVITATION

• Gravitational force decreases as distance between
  two objects increases.

• Gravitational force increases as distance between
  two objects decreases.