Question

larks)
5. Collect at least six objects of different materials. Check them for their friction
by sliding an object on their surfaces. Now arrange them according to their friction
(high to low). How their friction can be reduced? Suggest some methods according
to the materials
(6 marks)​

Answer 1

Answer:

Methods of reducing friction are :

POLISHING : When we Polish a surface, it's roughness decreases. The surface becomes smooth and friction gets reduced. We also sometimes rub the surface with a fine sand paper to reduce their unevenness.

LUBRICATION : We all know that when a few drops of oil are poured on the hinges of a door, the door moves much more smoothly. Bicycle and motor mechanics use grease between the moving parts of these machines. In all these cases, we want to reduce friction in order to increase efficiency.Oil-like substances, which help to reduce friction when put on a surface, are called lubricants. Lubricants can be liquid, semi liquid, solids.

BALL-BEARING: We know that rolling friction is smaller than sliding friction. Sliding can be replaced by rolling , by use of ball bearingso. For example, we use ball bearings in shafts of motors, dynamos, axles of vehicles and so on.

Explanation:

Hope you got ur Ans

Answer 2

Answer:

The answer is as follows .

Explanation:

Six objects are :

1. wooden block
2. wooden block aluminum block
3. wooden block aluminum block iron block
4. wooden block aluminum block iron block Copper balls
5. wooden block aluminum block iron block Copper balls lead balls
6. wooden block aluminum block iron block Copper balls lead balls rubber block.

Methods to reduce friction :

The various methods used to reduce friction are:

• Objects that move in liquid, such as boats, planes, and cars, have a streamlined body shape and reduced liquid to reduce friction between the objects' bodies.
• By polishing the surface, the surface becomes smoother and friction can be reduced.
• Lubricants such as oils and greases can be used to reduce friction between surfaces.
• When rolling an object on a surface, ball bearings can be used to reduce friction between the rolled object and the surface.

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