Sliding friction, rolling friction, and fluid friction

“Every object continues in a state of rest, or in a state of motion in a straight line at a constant speed, unless it is forced to change that state by forces acting upon it.”

1. 
   Who really came up with the Law of Inertia?
   
2. 
   How do objects move?
   
3. 
   Why do things eventually stop?
   
4. 
   Why can’t you tell you are moving in an airplane?
   

1. 
   What is the formula for force?
   
2. 
   What are the units for force in the long form?
   
3. 
   What is the unit in short form?
   

4. 
   Which one do you think will go farther? (stop the video and make a prediction)
   
5. 
   Which one went faster and farther? Why?