1. Gravity: A Force of Attraction
Chapter 5 Section 4
Gravity: A Force of Attraction

2. Gravity:
A force of attraction between objects that is due to their masses.

3. All Matter is Affected by Gravity
All matter has mass.
Gravity is a result of mass.
All matter experiences gravity.
All objects experience an attraction toward other objects.

4. Why don’t we feel the attraction to other objects?
The mass of most objects are too small to cause an attraction large enough to move objects toward each other.
The earth causes a noticeable attraction.
You must apply force to overcome the gravitational force from the earth.
Earth’s gravitational
Force pulls objects towards
The earth.

5. The Law of Universal Gravitation
Sir Isaac Newton
The Core of an Idea
Apple falling from a Tree
There had to be an unbalanced force to the apple
To make it fall.
A Law is born:
Called “Universal” because it
Applies to all objects in the
Universe.

6. The 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 and the distance between them.
Gravitational Force increases as Mass Increases.
Moon is smaller than the earth and has less gravitational force.

7. The Law of Universal Gravitation
Gravitational Force Decreases as Distance Increases.
Sun is 300,000 x’s larger than the earth, why doesn’t it pull us toward it rather than the earth? It is too far away.
If the sun’s gravitational force was not as large, the planets would not orbit the sun.

8. Weight is a Measure of Gravitational Force.
Weight: a measure of the gravitational force exerted on an object.