Methods for changing the amount of friction and what methods are used to increase friction

The magnitude of sliding friction is related to the positive pressure between the two objects and the surface condition of the two objects, the greater the pressure, the rougher the surface, and the greater the friction.

1.The rougher the joint surface of the object, the greater the friction. For example, the pattern of the sole and the tire.

When the car is driving on the road, the tires come into contact with the rough asphalt surface, so that the friction increases. When the car is driving on a snowy or watery surface, the friction will be reduced. Therefore, it is necessary to pay attention to safety in rainy and snowy days.

2.Reduce the roughness between the contact surfaces; The fan hinge should be made very smooth. When playing sand curveball, if you want the ball to slide fast, you need to put more sand on the table.

This reduces friction. If there is less sand and the friction surface is large, the ball will slide slowly. In ancient times, direct friction between the wheel and the axle was easy to damage, but now there is a bearing between the wheel and the axle, which reduces friction, and the car is not easy to be damaged when it is fast.

Friction is a relatively troublesome force in mechanics because it has a lot of content and a wide range in the college entrance examination. Through visual examples, we can understand the method of judging the direction of friction and the calculation of size.

Contact surface material (change the kinetic friction factor).

Add lubricant (change the kinetic friction factor).

Change the amount of pressure.

Change the direction of pressure.

Sliding friction is changed to rolling friction.

Rolling friction changes the moment relationship.

Dry friction is changed to wet friction.

Static friction changes the force relationship.

In the case of dynamic friction: 1Changing the kinetic friction factor (e.g. changing the contact surface material).

2.Change the positive pressure.

Friction formula dynamic friction factor + pressure, either to reduce the pressure or not to reduce the kinetic friction factor,

Reduce roughness by 1. Add lubricating oil 2Burnish.

Reduce the pressure on the contact surface.

Turn sliding into scrolling.

1.Changing the kinetic friction factor (e.g. changing the contact surface material).

2.Change the pressure.

Change the roughness of the contact surface, change the pressure.

1.Change the coefficient of dynamic friction.

2.Change the pressure.

Examples of reducing friction are:

1. There is an uneven pattern on the sole, which increases the friction by increasing the roughness of the contact surface under the condition that the pressure remains unchanged.

2. Paste rubber on the table tennis racket to make the contact surface rough, and when the pressure is unchanged, Huigao can increase the friction.

3. The car is stuck in the mud, and the grass is put on it to make the car come out and increase the friction.

4. Sprinkle sand on the ice in winter to increase friction.

5. Weightlifters apply magnesium carbonate powder on their hands before the competition to prevent slipping and increase friction.

There is an elastic force between two objects in contact with each other, and when they are about to move relative to each other or have a tendency to move relatively, a force will be generated on the contact surface that hinders the relative motion, and this force is called friction.

The conditions for friction are: objects are in contact with each other; There is a mutual extrusion between objects; rough contact surfaces of objects; There is a tendency or relative motion between objects to move each other.

1. Methods to increase friction.

When people walk, they should use the friction between the sole and the ground, this friction is beneficial, in order to increase the friction, there are uneven patterns on the sole, so that the contact surface is rougher.

In order to make the car stop quickly after braking, it is necessary to use the friction between the tires and the ground, and the road is slippery in snowy days, the friction is small, and it is not easy to stop when braking, so it is easy to cause traffic accidents. In order to reduce the occurrence of such accidents, people make uneven patterns on the tires, and when it snows, they also sprinkle ash on the road to increase friction and prevent the car from skidding.

Gymnasts or weightlifters should apply magnesium carbonate powder to their hands before competitions to increase friction and prevent slipping.

The increase in friction between the tug-of-war and the ground becomes the key to victory or defeat. Wearing shoes with embossed soles can increase friction; And the heavier the weight of the players, the greater the pressure on the ground and the greater the friction.

All of the above are beneficial frictions that help people, so we need to make reasonable use of them and find ways to increase them.

1. Use a rougher surface to improve the dynamic friction factor.

2. Raise the pressure.

The frictional force f is equal to the pressure multiplied by the coefficient of friction. The friction can be increased by increasing the pressure and increasing the coefficient of friction.

For example, when holding the bottle in the hand, the greater the grip, the less likely the bottle will be to slip off; Another example: there is a convex and concave pattern on the sole, which increases the friction coefficient between the sole and the ground, increases the friction between the shoe and the ground, and prevents walking and slipping.

Examples of increasing friction in life:

1. The sole and tires are engraved with concave and convex patterns. In order to increase friction and anti-slip.

2. Gymnasts or weightlifters should apply magnesium carbonate powder on their hands before competing.

3. Install snow chains on vehicles driving on ice and snow roads.

4. The rough surface of the tile is anti-slip by friction.

5. The brake uses friction.

Examples of reducing friction in life:

1. Skate blades glide on the ice.

2. Oil a mechanical watch after wearing it for a long time to reduce friction.

3. Maglev train to reduce friction.

4. The fan turning positive shaft should be very smooth, which can reduce friction.

5. Install rolling bearings and lubricating oil on the rotating part of the machine to reduce friction.

There are two factors that affect the magnitude of friction:

1. The magnitude of friction is related to the pressure between the contact surfaces, and when the roughness of the contact surface is constant, the greater the pressure, the greater the friction.

2. The magnitude of friction is related to the roughness of the contact surface, when the pressure is constant, the rougher the contact surface, the greater the friction.

The friction between solid surfaces is divided into sliding friction, rolling friction, static friction, rolling friction and rotational friction. In engineering, lubricants are used to reduce friction.

If two surfaces rubbing against each other are separated by a layer of liquid, then liquid friction can occur between them, and mixed friction can occur if the liquid is not completely isolated.

The air cushion guide rail uses gas friction to work, and the working principle of both lubricating oil and air cushion guide rail uses "friction with liquid or gas (i.e. fluid) instead of solid friction" to work.

Increase friction].

1.When the road is frozen, you can sprinkle some fine sand on the ice to make it safer.

2.Ride your bike and apply the brakes.

3.When rollerblading.

4.Hold the bottle firmly and increase the pressure.

5.Sprinkle sand on the road to increase the roughness of the contact surface.

6.Wrap a towel around the cap to increase the roughness of the contact surface.

7.Put things against the wall to increase the pressure.

8.When walking.

Reduced friction].

1.Lubricate the gears. The lubricating oil acts between the gears, changing their original contact mode to the friction between the lubricating oil and the gears, thus reducing friction.

2.When the rust is difficult to open, a small amount of oil can be injected into the keyhole to open easily.

3.When carrying a container, you can spread a few logs on the ground to make it easy to move.

4.When the zipper is not easy to pull, you can apply some paraffin wax on the zipper to pull it.

5.Spread some rosin on the violin.

6.Install ball bearings on the shaft of the machine.

7.Hovercraft use compressed air to form an air cushion that detaches from the water surface.

8.Add some lube between machines and machines.

In fact, increasing friction and decreasing friction are everywhere in life, and I just give you a reference

Examples of increasing bending friction in life:

1. The sole and tires are engraved with concave and convex patterns. In order to increase friction and anti-slip.

2. Gymnasts or weightlifters should be smeared with magnesium carbonate powder on their hands before the competition.

3. Install snow chains on vehicles driving on ice and snow roads.

4. The rough surface of the tile is buried and used to prevent slip by friction.

5. The brake uses friction.

Examples of reducing friction in life:

1. Skate blades glide on the ice.

2. Oil a mechanical watch after wearing it for a long time to reduce friction.

3. Maglev train to reduce friction.

4. The fan shaft should be made very smooth, which can reduce friction.

5. Install rolling bearings and lubricating oil on the rotating part of the machine to reduce friction.

The methods of increasing friction are to increase the pressure on the surface of the object, increase the roughness of the surface of the object, change the rolling friction to slippery cavity friction, change the wet friction to dry friction, and use external force to bond it. When two objects that are in contact with each other and are squeezed by each other, when they are in relative motion or have a tendency to relative motion, a force that hinders the relative motion or tendency to move will be created on the contact surface, and this force is called friction.

There are two causes of friction between solid surfaces: the mutual attraction of atoms and molecules on the solid surface (energy requirements for chemical bond recombination, glue force) and the resistance to each other caused by rough surface traces between them.