I understand that every force has an equal and opposite reaction, and the reason things can move is because the forces acts on different things. Also, F=MA is why the heavier object is accelerated less. The equal and opposite reaction to gravity pulling down towards the Earth's core on a book, is the gravity pulling up on the Earth's core toward the book, but because the Earth weighs about 5* 10^24 times more, there is basically no movement of the Earth, but there is a falling phenomenon for the book. Also, the reasons that things can't go through each other unless given enough force is because of mutual electrostatic repulsion (equal and opposite) between the electrons and nuclei on the surfaces. Also, the electrostatic attraction/covalent bonds between the molecules and atoms is what holds things together. Why does deformation occur if too much pressure (Force/Area) is exerted? Shouldn't the force be equally distributed throughout the object, and cause it to move, not deform or break? If you punch a wall, the wall is connected to the rest of the house, so it doesn't move very far due to the large mass, but if you hit it hard enough, why does it dent? Why do things break, if the electromagnetic force becomes stronger inversely proportional to the distance between the charges? If that were true, then the electromagnetic force would always become strong enough to stop the force being exerted on it. Also, how come you don't get pushed back very hard when you punch something if you are much less massive? What makes something easy to deform (like mud)? Is pressure more useful than total force? What causes the normal force exerted by a table onto a book resting on it, if the normal force is not a reaction force to gravity or to the electromagnetic force? Also, when something breaks due to having something too heavy resting on it, is it because the object could not provide sufficient normal force? Does that mean there is a maximum normal force for an object? How come you don't go flying upward if the electromagnetic force is so much stronger than gravity (relatively). When dealing with large masses, like the Earth, the gravity should actually exceed the electromagnetic force, so you should sink into the ground (both get stronger inversely proportional to the decrease in distance, so that doesn't make a difference). Why doesn't this happen, on a rigid surface? Is it because of tension force? What creates that? Is friction just electrostatic force caused by irregularities in the surface pushing on each other? Why do wider tires, or ones with more surface area (like treads) have more grip/traction? Is traction due to static friction or kinetic friction, on non-rolling bodies? Why is rolling friction so much less than kinetic friction, and why is the same true for kinetic and static friction (not from empirical observation, from theoretical deduction). Thank you in advance for the answers, and sorry for asking so many questions.