3.why is the surface of the earth in constant motion?

4.what are plates?

5.what is the definition of an earthquake?

6.earthquakes range from what to what?

7.how many types of forces are there? name them:

8.what is tension?

9.what is compression?

10.what is shear?

11.when do normal faults occur?

12.what happens along a normal fault?

13.how do reverse faults occur?

14.what happens along a reverse fault?

15.what happens at a strike-slip fault?

3. It's because of the heat underneath the crust of the Earth. Because heat rises, the molten rock and such underneath the crust rises to the top and then the movement underneath causes things on top to move. 

4. Plates are the different sections that the lithosphere has been cracked into. These plates once all fit together as a giant plate called Pangaea. 

5.  An earthquake is a sudden, sometimes violent shaking of the ground, as a result of the shifting of tectonic plates, or volcanic eruption. 

6. On the magnitude scale, earthquakes range from 2.5 or less (usually never felt but strong enough to be detected by seismograph) to 8.0 or higher. Causes extreme damage; enough to destroy whole cities at once if close enough to the epicenter. 

7. Depends on what kind you're looking for. I'd look it up for your specific topic.

8. To apply a forces to something, usually resulting in a stretch.

9.  The action of compressing something, to flatten or squeeze by pressure

10. A strain on the layers of something because of pressure, resulting in the shifting of those layers.

11. In areas undergoing extension or stretching. It's when the crust is extended. 

12.  The hanging wall drops relative to the footwall. 

13. This is what happens when the hanging wall rises relative to the footwall. (The opposite of a normal fault)

14.