Is Normal Force a Contact Force Despite Atomic Repulsion?

In summary, normal force is considered a contact force, but it also has to do with the repelling of atoms. Technically, if two objects are close enough for contact forces to exist, they are considered "touching" even though there may be a minuscule space between them. Contact forces, such as normal forces, belong to the family of electro-magnetic forces and on an atomic scale, they never truly touch due to the repulsion of electrons. However, for practical purposes, they can be considered as touching on a macroscopic scale.
  • #1
Physics4Eva
13
8
Guys I was just wondering if normal force is a contact force. Obviously it is considered a contact force but it also has something to do with the repelling of atoms. In my mind, normal force is a fundamental truth, but technically, are two objects touching or is there a minuscule space between the object.
 
Physics news on Phys.org
  • #2
Physics4Eva said:
Guys I was just wondering if normal force is a contact force.
Yes.

Physics4Eva said:
are two objects touching or is there a minuscule space between the object
If they are close enough for contact forces to exist then they are “touching”. It may be that contact forces have some small non zero range.
 
  • Like
Likes vanhees71 and Physics4Eva
  • #3
Thanks for the quick reply:wink:
 
  • #4
Normal forces, and other so-called contact forces like tension and friction forces, belong to the family of forces called electro-magnetic forces (as distinguished from the strong and weak nuclear forces, and the ‘action at a distance’ classical gravity “force”). Being an electromagnetic force, contact forces actually never touch each other on the atomic scale, due to the repulsion of electrons between the objects in contact. For all practical purposes however, they can be considered as touching on the macroscopic scale.
 
  • Like
Likes vanhees71 and Physics4Eva
  • #5
Very intuitive😜
 
  • #6
Physics4Eva said:
... but technically, are two objects touching ...
What is your "technical" definition of touching?

 
  • Like
Likes Physics4Eva and Dale

1. What is normal force?

Normal force is the force exerted by a surface on an object that is in contact with it. It is always perpendicular to the surface and acts in the opposite direction of the force applied by the object.

2. How is normal force calculated?

Normal force is calculated using the formula FN = mgcosθ, where m is the mass of the object, g is the acceleration due to gravity, and θ is the angle between the surface and the force of gravity.

3. What is the difference between normal force and weight?

Normal force and weight are two different types of forces. Normal force is the force exerted by a surface on an object, while weight is the force of gravity acting on an object. Normal force is always perpendicular to the surface, while weight is always directed towards the center of the earth.

4. Is normal force always equal to weight?

No, normal force is not always equal to weight. Normal force depends on the surface and the angle of the surface, while weight depends on the mass of the object and the acceleration due to gravity. However, in some cases where the object is at rest or moving at a constant velocity, the normal force may be equal to the weight.

5. What is the significance of normal force in physics?

Normal force is an important concept in physics as it helps us understand the forces acting on objects in different situations. It is crucial in determining the motion of objects on inclined surfaces and in calculating the forces involved in collisions. Understanding normal force is essential in many areas of physics, including mechanics and engineering.

Similar threads

Replies
4
Views
3K
Replies
1
Views
691
Replies
7
Views
1K
  • Classical Physics
Replies
7
Views
863
Replies
19
Views
863
  • Introductory Physics Homework Help
Replies
7
Views
2K
  • Classical Physics
Replies
10
Views
2K
Replies
9
Views
1K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Classical Physics
Replies
12
Views
2K
Back
Top