1. Gravity
What is it?
Gravity is……

2. Gravity …. ..is a force pulling on an object
Sun’s force pulling on planets to keep them in orbit
Earth’s force pulling on the moon
Attracts all objects toward each other

3. Sir Isaac Newton
discovered that every object in the universe attracts every other object
Force of gravity is measured in Newtons because of this discovery
The strength of force of gravity depends on:
Mass of objects
Distance between objects

4. Vocabulary Mass Weight Inertia Amount of matter in an object
Mass does NOT change
Weight
Force of gravity on an object
DOES change depending on location
Ex) you would weigh 1/6 of your Earth weight on the moon. This is because the moon is far less massive than Earth so the pull from the moon is less than Earth.
Inertia
Object in motion stays in motion until a force is acted on it

5. Gravity and Distance…what’s the relationship?
Strength of gravity depends on distance between 2 objects as well as their masses
Force of gravity decreases as distance increases. They are disproportional!
Ex) If distance DOUBLES, the gravity will be ¼ of its original value

6. Application of skills--
What would increase the force of gravity between 2 objects?
Decrease the distance or increase the mass
What would decrease the force of gravity between 2 object?
Increase the distance or decrease the mass

7. Gravity (visuals)
Gravity attracts all things together.
2 M
2 M

8. Increase in mass=increase in force

9. Increase in distance=decrease in force
2 M
2 M

10. Inertia and Gravity…. INERTIA
*the greater the mass of an object=greater the inertia
*the more inertia an object has, the more force is needed to stop it
*Without gravity, inertia would allow Earth to move away from the sun and the moon to move away from Earth in a straight line.
*Inertia and gravity keeps the Earth from crashing into the sun
*Inertia and gravity keeps the Moon from crashing into Earth
*Newton’s 1st Law of Motion
*an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless another force acts on it.
*car analogy

11. Food for Thought….Exit Slip!
Would the gravitational force be slightly greater if you were standing on land at sea level OR at the top of Mt. Kilimanjaro? Why?