2. What is evident. The Earth and the moon have existed for about 4
What is evident. The Earth and the moon have existed for about 4.5 billion years. During this time the moon has been orbiting the Earth in a circular dance.

3. What is not so evident: stellar tug of war
What is not so evident: stellar tug of war! - the Earth and the moon are in a violent game of tug of war. -each aggressively pulling on each other

4. Is seen in the rise and fall of Earth’s tides in oceans and rivers.
But how does this relationship happen?
Moon’s pull on Earth

5. Sir Isaac Newton made a mathematical model of the moon and Earth relationship
The mathematical equation is called Newton's Universal law of Gravitation.

6. m1 m2 F1 F2 r Newton's Universal Gravitational law
states that the force of gravity (Fg)
Between two objects is equal to the universal gravity constant(G) G = 6.67 x Nm2
kg2
times the mass of each object (M1,M2) all divided by the squared distance between the two objects (r2). m1 m2 F1 F2 r

7. The gravitational force is :
The gravitational force is proportional to the product of their masses.
As the product increases so does their gravitational force.
Also as the product decreases the gravitational force will decrease as well.
The force is inversely proportional to r2
That means as the distance increases the gravitational force decreases and vise versa.
The gravitational force is :

8. G” is a constant value used to calculate the force of gravity between two objects.
G = 6.67 x Nm2
kg2
“g” is the acceleration due to the force of gravity pulling on an object
“Fg” is the actual pull, or force, of gravity on an object. It is also the weight of an object.
“Pulling ‘g’s’ ” in an aircraft, or amusement park ride, is actually the measure of how many times your weight “Fg “ your body is experiencing.
Big G little g and Fg