# The origin of normal reaction

I want to know what actually is the origin of normal reaction between 2 objects. i have read about normal reaction from several books which generally mention it as a component of contact force which acts perpendicularly on the bodies when they are kept in contact. But never mention about its origin only mentioning that it is electromagnetic in nature. But how exactly is it a electromagnetic in nature?And how does it act ? And why does it act perpendicular to the surface only ?

Also please tell me the mistakes about my reasoning about normal reaction and is it viable to even talk about it this way or is it viable in some other context ?What i think is that when 2 bodies are kept in contact with each other there occurs some very slight deformations in the 2 bodies (as there is no such thing as a perfectly rigid body ) As a result of this deformation electrostatic restoring forces appear by virtue of which normal reaction is applied .

Also why it's properties are different from frictional force when both are the components of contact force?

Also Could someone please tell me some books in which these details about normal reaction and friction are mentioned , as i could not find them in several books in which i checked . It would be very helpful . Thx

• "And why does it act perpendicular to the surface only ?" This is by definition. The normal reaction force is defined as the perpendicular component of the contact force. The transverse portion goes by another name (friction). There is, of course, a good question in why the macroscopic rules for the two components of the contact force are different. – dmckee Aug 21 at 16:54
• As dmckee already pointed out, it is perpendicular by definition. As to the electrostatic nature of the force, I think you answered you own question in the last two sentences. – Bob D Aug 21 at 18:47
• @dmckee Good comments. Why not post it as an answer? – Bob D Aug 21 at 21:43
• @BobD Because I don't have time to discuss the mechanisms behind the contact force. Much less digging into the difference in behavior (and why it is not as stark as it initially appears). – dmckee Aug 21 at 21:47
• @BobD , So what I said about the restoring forces is right? – p0803 Aug 22 at 4:32