The discussion revolves around the effects of deformation on the net force between two masses, specifically when one mass is placed on top of another. The original poster questions whether the normal forces acting on the masses change if the lower mass is able to deform under the weight of the upper mass.
Participants are actively engaging with the concepts of force and deformation, with some suggesting that the initial net force leads to deformation, while others clarify that forces may balance once deformation ceases. There is a recognition of the complexities involved in the scenario, particularly regarding elastic versus plastic deformation.
Participants are considering the specific conditions under which the masses are analyzed, including the nature of the materials involved and the assumptions about their rigidity or deformability. The discussion also touches on the implications of weight force and gravitational acceleration in this context.
Consider the vertical balance of forces on each mass. Can there be a net force on either?John781049 said:Homework Statement:: Suppose you have two masses m1 and m2 with m2 on top of m1. I understand the normal force acting on m1 will be m1g+m2g and normal force on m2 will just be m2g but wanted to know, is this only true for rigid masses? If m1 was able to deform from the weight of m2 above it (like a trampoline for example), would a scale underneath m1 register less weight now?
Relevant Equations:: Thanks
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Equal and opposite forces are quite able to deform objects.John781049 said:I think there is for m1 because it wouldn't deform otherwise.
Well, there is a net force initially then while m1 deforms but once it's stopped deforming forces are balanced? I think it would be like with a trampoline. If someone stands on the trampoline, there's a net force that causes the ropes to sag downwards when you land from each jump and once the trampoline doesn't sag anymore, it will propel you back up.haruspex said:Equal and opposite forces are quite able to deform objects.
What does ΣF=ma tell you about the consequences of a net force?
Yes.John781049 said:there is a net force initially then while m1 deforms but once it's stopped deforming forces are balanced?