friction

Topics: Force, Friction, Classical mechanics Pages: 5 (726 words) Published: November 29, 2013
﻿Session=2013-14

Physics Project
Topic: Friction

Submitted To; Submitted By;

Acknowledgement
The success and final outcome of this project required a lot of guidance and assistance from many people and I am fortunate to have got this all along the completion of my project work. I respect and thank for giving me an opportunity to do the project work on ‘Friction’. I am extremely grateful to him for providing such a nice support and guidance. At last, I want to thank my family and my friends for their support in this project.

Certificate
This is to certify that of class , has prepared and submitted the Project Report enclosed herewith under my direct and close supervision and that this is a individual piece of work done by him. It has not been submitted to any other school or university, nor has been published at any time earlier. Date:

Teacher’s Sign- Principal Sign-

Index
Types of forces
Friction
Origin of force of friction
Types of frictional force
To calculate frictional force
Angle of repose equals to angle of friction

Types of Forces:

A force is a push or pulls acting upon an object as a result of its interaction with another object. There are a variety of types of forces.

Contact Forces
Action-at-a-Distance Forces
Frictional Force
Gravitational Force
Tension Force
Electrical Force
Normal Force
Magnetic Force
Air Resistance Force

Applied Force

Spring Force

Friction:
It is a force that always exists between any two surfaces in contact with each other. In general it is an opposing force that is set up between the surfaces in contact and it comes into play whenever a body moves or tends to move on another body.

The force of friction acts in the direction opposite to its motion of direction.

For example, if a book slides across the surface of a desk, then the desk exerts a friction force in the opposite direction of its motion. Friction results from the two surfaces being pressed together closely, causing intermolecular attractive forces between molecules of different surfaces. As such, friction depends upon the nature of the two surfaces and upon the degree to which they are pressed together. The maximum amount of friction force that a surface can exert upon an object can be calculated using the formula below: Ffrict = µ • Fnorm

Origin of force of friction

The surfaces which are thought to be smooth posses some small irregularities in the form of projections which get interlocked with each other and then in the action comes friction which opposes the motion.

Types of frictional forces:

There are two kinds of friction, based on how the two surfaces are moving relative to each other:
1. Static friction
The friction that exists between two surfaces that is not moving relative to each other. It opposes the impending motion i.e. the motion which would take place in the absence of friction.

2. Kinetic friction
The friction that exists between two surfaces that is moving relative to each other.

To calculate force of friction
Ffrict = µ • Fnorm
Where-

Ffrict: is the frictional force

µ: is the coefficient of friction (static or kinetic)

Fnorm: is the normal force

For static friction:

For kinetic friction:

Angle of friction:

The angle of friction can be defined as the angle which the resultant of limiting friction and normal reaction makes with normal reaction. It is

Tan θ = F/R

θ is the angle of friction

Angle of repose:

Angle of repose is defined as the minimum angle made by an inclined plane with the horizontal such that an object placed on the inclined surface just begins to slide.

Tan a = F/R

Here ‘a’ is the angle of repose.

Angle of...