Answers and Solutions

Answer

Creating a More Frictive Surface

Create a “rougher” or more adhesive point of contact. ...

Press the two surfaces together harder. ...

Stop any relative motion. ...

Remove lubrication between the two surfaces. ...

Remove wheels or bearings to create sliding friction. ...

Increase the fluid viscosity.

Reducing Friction. There are several ways to reduce friction: The use of bearing surfaces that are themselves sacrificial, such as low shear materials, of which lead/copper journal bearings are an example. Replace sliding friction with rolling element friction, such as with the use of rolling element bearings.

Answer

DEFINATION:
Friction is the force that opposes the motion of an object. 
To stop  moving  of a object, a force must be applied in the opposite direction  of motion. For instance, if you push your book across your desk, the book will move. The pushing force moves the book. As the book slides across the desk, it slows down and stops moving. The force that opposes the motion of the book  is called friction.

Friction force(F) = \(\mu R\)    [ R=   normal reaction ]

There are two types of friction –

• Static friction –  The friction which acts on rest bodies(not change their position w.r.t time).
• Dynamic friction -  The  frriction which acts on moving bodies.
  
  
  
  METHOD OF INCREASING FRICTION:  
  
  By making the surface rough :   We can increase friction by making surfaces rough

 Examples : (1) To increase friction-the tyres of a any vehicles are made rough .

                     (2) When a ground or surface become slippery after raining  it is                                                      made rough by spreading sand to increase the friction.

           METHOD OF DECREASING FRICTION: 

     Using of Lubricants: Friction between two surfaces can be decreased by using lubricants. A lubricant is a substance  which forms a thin layer between the two surfaces in contact. Thus the friction between to surface reduced. 

     By  polishing the surfaces : Friction between two surfaces can be reduced by polishing the surfaces.

    By using  Ball-bearing:  we know that , rolling friction less than the sliding friction consequently in rotating machinery, the shafts are fixed on the ball bearing so that the friction can be reduced considerably. For example- the free wheel of a cycle, the axle of a motorcar, the shafts of the motor dynmo etc. are provided with ball-bearing.