The discussion centers on the effects of deformation on the net force between two masses, specifically when one mass (m2) is placed on top of another (m1). It is established that the normal force acting on m1 is the sum of the weights of both masses (m1g + m2g), while the normal force on m2 is simply m2g. When m1 deforms under the weight of m2, there is an initial net force that causes deformation, but once deformation ceases, forces become balanced. This indicates that a scale beneath m1 would not register less weight once the deformation stabilizes.
PREREQUISITESThis discussion is beneficial for physics students, educators, and engineers interested in mechanics, particularly those studying force interactions and material properties under load.
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
S
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?