Friction Force with Examples

Friction Force:

Friction force results from the interactions of surfaces. Irregularities in the structure of the matters causes friction force. These irregularities can be detected in micro dimensions. You may not see any irregularity on the surface of the material however, it does exist. Friction force is always opposite to the direction of motion and tends to decrease net force. All materials have their own friction constant in other words friction force depends on the type of materials. Another factor affecting friction force is the normal force. When you apply a force to an object, then friction force becomes active and resists with the force of having opposite direction to your net force.

 

friction force

 

 

 

 


 

We can calculate the friction force by this formula;

Where, µ is the coefficient of friction and it depends on the type of material. Fnorm is the reaction of the surface to the object because of its weight.

Ffriction≤ µ.m.g We assume that weight as m.g, however if the object is on an inclined plane than we take the vertical component of the mass while calculating weight.

Friction can be studied under two topics static friction and sliding friction. Surfaces apply different friction constant when the object is at rest and sliding. Interestingly, the friction constant of the objects at rest is higher than the friction constant of the sliding objects. The sliding friction force is calculated by using the µ and the Fnorm normal force that surface apply to the object.

Ffriction= µsliding.m.g sliding

Friction force also exists when there is no motion. If two objects are in contact then we can talk about friction force there is no need for motion. In static friction force, two objects are in contact however there is no motion in other words object does not slide on the surface. You all experience the static friction in daily life. For example, suppose that you push a huge box, which is on the carpet, however, box does not move. Static friction becomes exist when you apply a force to the object. The amount of the static friction is equal to the amount hat you apply and the direction is opposite to the direction of the motion. If you increase the applied force until one point static friction also increases. We will calculate this limit point by the formula given below.

Ffriction? µstatic.m.g static

We use symbol instead of =, because static friction changes with respect to the applied force. It has the value of 1 to the limit value. We calculate the limit value by the formula given above. Most of the time magnitude of static friction is greater than magnitude of sliding friction for same surfaces. We solve some problems related to the friction and Newton’s law of motions.

Example50N of force is applied to the 6 kg box. If the coefficient of friction is 0, 3, find the acceleration of the box.

friction force example

 

 

 

 

 


 

friction force example solution

 

 

Free body diagram of the system is given above. From this diagram we find the normal force of the surface and friction force.

free body diagram

 







Fnormal=mg-Fy

Fnormal =60N-40N=20N

And friction force is;

Ffriction=µ.Fnormal=0, 3.20N=6N

Net force in –Y to Y is zero, in other words box is in equilibrium in this direction. However, in –X +X direction net force is not zero so there is a motion and acceleration in this direction.

Fnet=m.a

Fx-Ffriction=m.a

30N-6N=6kg.a

a=4m/s²

ExampleFind the acceleration of the system. (µ=0,4, sin37º=0,6, cos37º=0,8 and g=10m/s²)

friction force example

 

 

 

Dynamics Exams

 


Related

examples of friction in daily life
sliding friction examples
examples of sliding friction
examples for friction force
examples of forces Fnormal Fapplied Ffriction
daily examples for force of friction
examples of friction force
"sliding friction" "examples"
formula for magnitude of static friction
examples of friction in and around the home
three examples of friction in daily life
friction force on free fall
everyday life examples of friction
examples of friction physics
example of friction solution
friction force to point in the direction of motion
examples of friction in everyday life
force static friction formula
dyanimcs ecams forces
"Friction force is always opposite to the direction of motion and tends to decrease net force"
experience friction force
physics dynamics formulas net force friction applied force
example frictional force
worked solution for magnitude of frictional force
Frictional force equation
inclined planes and static friction problem solutions
daily use frictional force
examples of friction force in our daily life
power of friction examples
sample solved problems about friction
friction objects home
friction force examples
dynamics friction examples
friction force
how find the kinetic friction force tutorials
friction daily life
examples of friction surfaces
hats with friction word
charging by friction everyday life examples
examples with solutions of friction
physics coefficient sliding cheat sheet
why is friction normal=mg
limiting frictional force equation
friction motion examples and solutions
example exercises about kinematic friction
examples applying friction in life
magnitude frictional force examples
tutorial on force of friction
examples of friction
friction everyday example