Every object around you is attracted to you. In fact, every object in the galaxy is attracted to every other object in the galaxy. Newton postulated and Cavendish confirmed that all objects with mass are attracted to all other objects with mass by a force that is proportional to their masses and inversely proportional to the square of the distance between the objects' centers. This relationship became Newton's Law of Universal Gravitation.

Procedure: https://phet.colorado.edu/sims/html/gravity-force-lab-basics/latest/gravity-force-lab-basics_en.html
1. Take some time and familiarize yourself with the simulation. Notice how forces change as mass changes and as distance changes.
2. Change the mass and distance of each object as shown in the table below and record the force in Newtons.
Mass Object 1 (billion kg)
Mass Object 2 (billion kg)
Distance (km)
Force (N)
2
4
3

4
8
3

7
3
6

7
7
6


How do the values compare? ____________________________________________________

Use the simulation to help you answer the following: (circle the answer)
1. Gravitational force is always attractive/repulsive.
2. IF a gravitational force exists between two objects, one very massive and one less massive, then the force on the less massive object will be greater than/equal to/ less than the force on the more massive object.
3. As the distance between masses decreases, force increases/decreases.
5. Doubling the mass of both objects would result in the change in force of 4x /2x /no change/ ½x/ ¼ x
6. Doubling the distance between two objects will change the force of 4x /2x /no change/ ½x/ ¼ x

Conclusion Questions:
1. What general rule can you write to explain the forces between objects of different masses?


2. Predict what would happen if either humanoid moved further away from the other object.


3. Apply: If the moon were twice as massive as it is (about 1/6 of the mass of Earth), how would that change gravitational pull on the Earth?