B A Question about Effect of Force on Rigid Bodies....

[Kaneki123]

Okay...I have a simple question that, if we apply a force to a wall, then according to F=ma, the wall should have some acceleration at all the points we are applying the force...My question is that since the wall does not move move back, does this acceleration only result in a slight deformation of wall (something hard to notice) or is the wall so ''rigid'' that it does not ''allow this acceleration''?

 

[hilbert2]

In the real world, there are no objects that are perfectly rigid and fixed in place. In special relativity this becomes especially obvious, see https://en.wikipedia.org/wiki/Ladder_paradox#Ladder_paradox_and_transmission_of_force .

 

[Dr.D]

You started with F=ma, but really you should start with sum F = m*a. When you apply a force in one direction (not enough to move the wall), the supports for the wall develop and equal force in the opposite direction. This way, the sum of forces remains zero, and hence no acceleration.

 

[Khashishi]

The wall is probably attached to the ground. When you push the wall, the ground pushes back. Now, if you are standing on the ground, then when you push the wall with a forward force, you push the ground with a backward force with your feet. These cancel, so the ground doesn't move. Irregardless, the ground is so big and heavy you wouldn't notice if it did move a little.