10 Examples of Contact Force
A contact force is a force that acts between two objects that are in contact with each other. Contact forces can be either attractive or repulsive and they can be either static or dynamic. Static contact forces hold objects together, while dynamic contact forces cause objects to move.
When you push a box across the floor, the force you are applying is a contact force. When you jump, the force that pushes you up into the air is a contact force.
Examples of Contact Force
These are 10 main examples of contact force.
1. Normal Force
One of the best examples of contact force is normal force. This force occurs when an object is in contact with a surface and pushes against it perpendicular to the surface. For example, when you stand on the ground, the ground exerts a normal force on your feet to support your weight.
2. Frictional Force
Frictional force opposes the relative motion or tendency of motion between two objects in contact. It can be kinetic friction (when objects are sliding past each other) or static friction (when objects are not moving relative to each other).
3. Tension Force
Tension force is the force transmitted through a rope, string, or cable when it is pulled tight. For example, the tension in a rope holding a hanging weight.
4. Applied Force
When you push or pull an object, you are applying force to it. This force occurs through direct physical contact.
5. Drag Force
When an object moves through a fluid (like air or water), it experiences a drag force in the opposite direction of its motion. For instance, a swimmer experiences drag force when moving through water.
6. Elastic Force
This force occurs when a spring or elastic material is compressed or stretched. The force is proportional to the displacement from the equilibrium position.
7. Buoyant Force
When an object is submerged in a fluid (like water), it experiences an upward buoyant force equal to the weight of the displaced fluid. This force is what allows objects to float.
8. Shear Force
Shear force occurs when two layers of a material slide past each other in opposite directions. It’s responsible for the deformation of materials under stress, like when you cut through an object with a knife.
9. Electromagnetic Force
When two objects with electric charge come into contact, they can exert electromagnetic forces on each other. For instance, when you rub a balloon against your hair, it can stick to the wall due to electromagnetic forces.
10. Normal Stress
In the context of materials and mechanics, normal stress is a force per unit area that is applied perpendicular to a surface, causing deformation.
These are some common examples of contact forces, and they play a fundamental role in understanding the physics of interactions between objects.