Static friction

When there is a propensity of relative motion between the two surfaces but no relative motion between the two contact surfaces, static friction occurs. An object’s static friction force opposes its impending motion relative to the surface. When motion arises in an object, it is referred to as static friction. When we push a table on the ground, for example, it does not move. It maintains the object’s equilibrium It opposes the tendency of a thing to move.. Because it increases instantly and equalises the applied force, static friction is also referred to as the self-adjusting force.

Friction

friction refers to the resistance a surface provides to an object moving or attempting to move across it. It works at the place where two surfaces meet. It’s called a contact force because it necessitates physical connection between two moving surfaces. Friction is a contact force that opposes the relative motion of two body who touches each other  all times. It behaves in the opposite direction of the body motion. For taking an instance, When we throw a box on the ground at  the right direction, the force of resistance on the box will work on left side , and it will work at the point of contact.

Causes of friction

Every surface has imperfections at the microscopic level. Irregularities are little hills and dells (small projections) on an object’s surface. These imperfections on the surface make it rough and prevent a surface from moving over another. This occurs as a result of abnormalities on one surface interlocking with irregularities on another. This occurs as a result of abnormalities on one surface interlocking with irregularities on another. When we press firmly on two surfaces in contact, the interlocking between them rises, resulting in an increase in friction force.

Types of friction

Static Friction 

When motion arises in an object, it is referred to as static friction. When we push a table on the ground, for example, it does not move. It maintains the object’s equilibrium. It opposes the tendency of a thing to move. the object moves if the applied force reaches a particular upper limit. Because it increases instantly and equalises the applied force, static friction is also known as the self-adjusting force. The static limiting friction is the maximum bound or maximum value of static friction.it is represented by fs. The normal reaction between the two surfaces in contact determines the static limiting friction.

 F∝R  

i.e. FS = S R

here R =normal reaction 

and S = coefficient of static friction

The coefficient of friction having no  dimensional quantity whose value is determined by the surface conditions and material properties of two objects in contact.

Sliding or Kinetic Friction

Static or kinetic friction is the force of friction that opposes the relative motion of two objects in contact. Consider a box that is falling down an inclined plane. The sliding value is less than the static value in this case.

The formula of kinetic friction is as follows:

 fk= k R= k mg

Here R = normal reaction

k = coefficient of sliding friction and m = mass of the body 

And g = acceleration due to gravity.

Rolling friction

Rolling friction occurs when an object rolls over another object’s surface Consider a young boy pushing a cart. The force is less than the static and sliding values in this case. This is due to the fact that in the case of rolling friction, the contact surface area is the smallest.

The weight of the rolling object has a direct relationship with rolling friction. As the radius of the rolling item shrinks, it increases.

Properties of static friction

 It is simply an electrostatic force between two surfaces that never causes motion; instead, it only responds to motion based on the types of materials in contact (- the coefficient of friction) and the net force. The direction of motion is irrespective of the area of the surfaces in contact when normal pressing the two surfaces in touch (N) acts parallel to the surfaces that are (or may have the potential to be) moving with respect to each other.

Because the static friction force is changeable and dependent on the external forces acting on an object, static friction is delicate.

The static friction force grows to match the force as you press harder. The book eventually moves as the maximum static friction force is reached. The static friction force always acts in the opposite direction to the direction in which the body moves or attempts to move. Friction is a self-adjusting force that increases in proportion to the applied force, gradually equalising and opposing it until the motion begins. When one body simply moves, the force of friction between the surfaces in contact is maximum. Friction is a force that can be used to reduce or eliminate friction. The static friction is determined by the nature of the surfaces in contact but is unaffected by their area.The normal reaction N is comparative to the static force, i.e. with an increase in the normal force, the maximum external force endured by an object without having to move also increases.

Conclusion

When there is a propensity of relative motion between the two surfaces but no relative motion between the two contact surfaces, static friction occurs. friction refers to the resistance a surface provides to an object moving or attempting to move across it. The normal reaction between the two surfaces in contact determines the static limiting friction. Static or kinetic friction is the force of friction that opposes the relative motion of two objects in contact. The static friction force grows to match the force as you press harder