Mada za sehemu hiiFrictionMada 3
- Concept of Friction
- Types of Friction
- Laws of Friction
Friction is the force, which opposes (resists) motion of the body for example: If a block of wood is placed on a table, it remains at rest unless an external force acts upon it.
The applied force must exceed the maximum friction force between the block of wood and the table if the block is to be moved along the table.
Friction force between two surface in contact exists only when there is relative motion between the two contacting surface.
The friction between two surfaces exists because of the nature of the surface of the bodies in contact. (Strictly speaking all surfaces are rough because they are made up of peaks and valleys)
When one body is pushed against another, the peaks of one surface have to rise up over the peaks of the other surface. Hence opposition to motion or friction occurs the force acting to restore the bodies to their original position.
Advantages of friction
- It helps in walking process (because friction force stop us from slipping over).
- It helps cars to move on roads easily due to friction between car tires and road (makes a car stay on road)
- It helps in car braking system. Brakes rely on friction between the brake drum or pads and the wheels. In a bicycle, there are brake pads, which clamp onto the wheel to slow it down.
Disadvantages of friction
- Cause machinery to heat up and can cause wear and tear.
- Cause machinery to be less efficient.
- Cause machinery to produce noise.
The different methods of reducing friction between surfaces includes the following:
- Polishing: Polishing the surface, reduces the irregularities and hence, reduces friction.
- Lubrication: It provides a layer of the lubricant on which the bodies can easily slide.
- Use of ball bearing or roller bearing: Roller bearing help to convert sliding friction into a milder form-rolling friction. Rolling friction is lesser than sliding friction.
- Streamlining: Fast cars, boats, planes etc., have a streamlined body. This is to allow air (or water in the case of boats) to easily flow by, without offering much resistance. Flying birds have streamlined bodies.
- Use of correct combination of surfaces in contact: Use of alloys on moving and sliding parts reduces friction because alloys have a low coefficient of friction.
- It is a simple cylinder on which a body to be pulled RESTS.
- It is used to eliminate sliding friction.
- Conveyor belts use metal rollers.
- These are rollers that are fixed to a moving body, held in place by cylinders or axles, which are threaded in their centers. Example; a trailer towed by vehicle.
- Wheels are used to eliminate sliding friction.
- They are used to reduce friction (the friction between surfaces can be reduced by smoothing and polishing the surfaces in contact).
- In order to make surfaces slippery, a lubricant such as oil or graphite is used. Oil and Grease are commonly used in vehicles and machines to reduce friction between moving parts. In engines, differential air is also an effective lubricant in machine.
Mwalimu
Unasoma somo hili? Niulize nikuelezee chochote kilichomo.
Ingia ili kumuuliza Mwalimu wa AI wa Sonza kuhusu mada hii.
Ingia ili kuuliza