Friction

This is because of the force of friction between the brake and the wheel of the moving vehicles.

It is difficult to walk on a wet floor because layer of water makes floor smooth. The coating of water reduces the friction and the foot cannot make a proper grip on the floor and it starts getting to slip on the floor.

Friction: Friction is the force which resists the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.

Friction depends partly on the smoothness of the contacting surfaces, a greater force being needed to move two surfaces past one another if they are rough than if they are smooth. However, friction decreases with smoothness only to a degree; friction actually increases between two extremely smooth surfaces because of increased attractive electrostatic forces between their atoms. Friction does not depend on the amount of surface area in contact between the moving bodies or (within certain limits) on the relative speed of the bodies. It does, however, depend on the magnitude of the forces holding the bodies together.

Dragging a mat when nobody is sitting on it easier than dragging the same mat when a person is sitting on it.

Sliding friction is slightly smaller than static friction because two sliding objects find less time to get interlocked against each other’s irregularities of surfaces as a result of which they experience less friction.

We could not write with chalk on board.

Striking a matchstick produces fire by friction.

Friction produces heat, when a machine is operated, heat is generated which causes much wastage of energy.

Soles of shoes are grooved so that a better grip is provided to the surface and thus can move safely and freely on floors.

The tyres of vehicles are treaded to provide better grip with the ground.

Powder is sprinkled on the carom board to reduce friction and increase efficiency.

A lubricant is a substance introduced to reduce friction between moving surfaces. It performs following functions

• Reduce friction
• Transfer heat
• Carry away contaminants & debris
• Transmit power
• Protect against wear
• Prevent corrosion
• Seal for gases
• Stop the risk of smoke and fire of objects

Friction can never be entirely eliminated, because no surface is perfectly smooth, there are always some irregularities present in it.

Rolling friction is the force that resists the rolling of a wheel or other circular object along a surface caused by deformations in the object and or surface. Generally the rolling friction is smaller than sliding friction. example: One of the most common examples of rolling resistance is the movement of motor vehicle tires on a road.

This is because rolling reduces friction; it is always easier to roll than to slide a body over another.

Friction occurs when two objects are moving relative to each other and rub together (like a sled on the ground) is called sliding friction.

Friction occurs when two objects are moving relative to each other and rub together (like a sled on the ground) is called sliding friction, but Rolling friction is the force that resists the rolling of a wheel or other circular object along a surface caused by deformations in the object and or surface.

Fluid friction describes the friction between layers within a viscous fluid that are moving relative to each other.

Frictions are reduced in machines by using rolling in place of sliding; ball bearings are used for this purpose.

The fluid friction can be minimised by giving suitable shapes to bodies moving in fluids.

Sportsman use shoes with spike to increase the friction so that the shoes do not slip while they walk run or play.

B will have to apply larger force since; B will experience more frictional force because heavy object will be pressed hard against the opposite surface and produces more friction.

The fluids like various liquids or air that is; gaseous medium also exerts frictional force known as Drag. To minimize the effect of this Drag, streamlining of the motion of the object in the fluid is necessary which can be achieved by modification in the shape of the body. Objects moving in fluids must have a special shape called streamlined shapes or aerodynamic shapes. Streamlined Shape or Aerodynamic Shape is that shape which overcomes the friction of fluid.

It is difficult to walk on a floor wet with soapy water because layer of soap makes floor smooth. The coating of soapy water reduces the friction and the foot cannot make a proper grip on the floor and it starts getting to slip on the floor.

It is difficult to walk on a floor wet with soapy water because layer of soap makes floor smooth. The coating of soapy water reduces the friction and the foot cannot make a proper grip on the floor and it starts getting to slip on the floor.

Spring balance consists of a coiled spring which gets stretched when a force is applied to it, stretching of the spring is measured by a pointer moving on a graduated scale, the reading on the scale provides us with the magnitude of the force.

Fluid friction describes the friction between layers within a viscous fluid that are moving relative to each other.

A moving ball on the ground stops after some times because of the force of friction.

Friction is an evil too because :

• It causes wear and tear in objects of our daily use including machines.
• It makes movement of heavy objects very difficult.
• We need to spend a lot of time and money for the maintenance of various machines in order to keep their friction low.