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Gravity and MotionSection 2: Pages 666
-669
2 major motions of the earth are? Which motion causes day and
night? What causes the seasons? What tilt is the earth at? What are solstices and
equinoxes? How do solstices and equinoxes
relate to seasons? How would seasons be different if
Earth were not tilted?
Earth In Space review
There must be a force acting between the two objects
A force is something that influences change
Isaac Newton identified that there must be a force acting between earth and moon
Force that keeps moon in orbit different than forces we are influenced by everyday. Why?
Why Doesn’t the Moon fly off into Space?
Gravity is a force that attracts all objects towards each other Newton did not discover gravity,
only realized it as a universal force Gravity is measured in newtons
Law of Universal Gravitation (Newton) states that every object in the universe attracts every other object
The strength of the force of gravity depends on two things: Mass and Distance
Gravity
Gravity, Mass and Distance
Mass amount of matter in an object Mass never changes
Weight is the force of gravity on an object Changes with gravity
My mass is 87.91 kg, my weight is 200 pounds Moon’s gravity is 1/6 of earth: what
is my mass and weight? Mass Increases force of Gravity
Increases Distance increases force of Gravity
Decreases
Gravity, Mass and Distance
Must be another force acting Inertia ability of an object to resist
change in motion Newton’s First Law of Motion
states that an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless acted upon by a force.
Why doesn’t Earth crash into the Sun?
2 factors: Inertia and gravity
Gravity pulls objects towards each other, preventing the moon from going in a straight line
Inertia makes the moon move forward
The combination creates the orbit
Why do Earth and Moon remain in their Orbits?
Planetary Orbits
What is the law of universal gravitation? What two factors determine the force of gravity
between two objects If the moon was closer to Earth, how would the
force of gravity between the Earth and moon be different?
What two factors act together to keep Earth in the orbit around the sun?
Why doesn’t Earth simply fall into the sun? How would Earth move if the sun suddenly
disappeared? Explain your answer.
Gravity and Motion Review