1. The Law of Universal Gravitation

2. Newton’s Law of Universal Gravitation
Newton Did not discover gravity, but he did discover gravity was universal. In other words, everything pulls on everything else. States: Every object attracts every other object with a force that for any two objects is directly proportional to the mass of each object, and indirectly proportional to the distance between them. In Simple Terms: The greater the mass, the greater the attraction. The greater the distance, the weaker the attraction.

3. Universal Gravitational Constant
There is a constant in value for this universal attraction Symbol: G Value: 6.67 X Nm2/Kg2
Formula: F= G(m1m2/d2) Where “d” is the distance between the center of mass for the two objects.

4. What is “G”? “G”, or the Universal Gravitational Constant
first measured by Henry Cavendish 150 years after Newton’s discovery of Universal Gravitation
Shows us that the force of gravity is a very weak force
Easy to notice with large masses, difficult to notice with small masses

5. Sample Question
The gravitational force of attraction between Earth and the sun is 1.6 x 1023 N. a) What would this force have been if Earth were twice as massive? b) What would the force be if the distance doubled?

6. Sample Question
Oliver, whose mass is 65 Kg, and Olivia, whose mass is 45 Kg, sit 2.0 m apart in their physics classroom. A) What is the force of gravitational attraction between Oliver and Olivia? B) Why don’t they drift towards each other?