The discussion revolves around the mechanics of forces acting on an object resting on a table, specifically addressing the conditions under which an object can be crushed despite having a net force of zero. The scope includes conceptual understanding of forces, structural integrity, and the implications of net force in relation to deformation.
Participants express differing views on the implications of net force being zero, with some emphasizing the distinction between net force and internal forces related to deformation. The discussion remains unresolved regarding the relationship between these concepts and the conditions for crushing.
Participants highlight the importance of understanding internal stresses and structural integrity, suggesting that the discussion may depend on definitions of force and deformation. There are unresolved aspects regarding how these forces interact in the context of crushing.
Typically, when people say "net force" they are talking about bulk motion (it makes the whole object move). It doesn't have anything to do with structural integrity. Nor does a net force of zero mean there is no force acting on the object -- obviously, the two forces are still there.Scheuerf said:If an object is resting on a table and is pushed downward it has an opposite and equal normal force that counteracts the applied and gravitational forces making the net force on the object 0. If the net force on an object being pushed against a table is 0, how can it be crushed?
No net force means that the center of mass will not accelerate. Each end can certainly accelerate inward In a crushing motion, that is not restricted by the second law.Scheuerf said:If the net force on an object being pushed against a table is 0, how can it be crushed?