The study of motions and the forces causing motion provide concrete experiences on which a more
comprehensive understanding of force can be based in grades 9–12. By using simple objects, such as
rolling balls and mechanical toys, students can move from qualitative to quantitative descriptions of
moving objects and begin to describe the forces acting on the objects. Students’ everyday experience
is that friction causes all motion to stop. Through experiences in which friction is reduced, students
can begin to see that a moving object with no friction would continue to move indefinitely, but most
students believe that the force is still acting if the object is moving or that it is "used up" if the motion
stop. (NS grades 5–8, 154)