# Which fundamental force is behind friction?

In day to day life we come across situations where friction is used. What is the fundamental force behind friction. For eg. which is the force behind interlocked objects like nut and bolt, which is the force behind holding an object.

If you can explain other similar practical situation in terms of fundamental forces it is very appreciated.

• Electromagnetic interaction. Jun 16, 2016 at 2:48
• Its the electromagnetic force. The 2 bodies between which there is some friction always have some irregularities on their surface. They are never perfectly smooth. To understand, we say that these irregularities fit in each other. Actually due to these irregularities the distance on atomic scale decreases and the electromagnetic force increases thereby giving rise to friction. If we smoothen the surfaces , the friction will decrease till a certain point. After which the friction increases incredibly. Think why Jun 16, 2016 at 3:44
• But atoms are generally neutral then how is there an electromagnetic force acting at atomic level between atoms. Jun 16, 2016 at 5:40
• What does it mean for two objects to touch? Jun 16, 2016 at 9:23
• Not exactly a duplicate, but see my answer to How is frictional force dependent on normal reaction? Jun 16, 2016 at 10:48