- Books Name
- Class-8 Science Book
- PathSet Publications
- CBSE Class 8
Wheels Reduce Friction
How Wheels Reduce Friction?
- We know that when an object rolls over a surface rolling Friction is produced which resists its motion on the surface. However, its magnitude is lesser than the static and sliding friction.
- Wheels are circulating objects that turn around a center point.
- The wheels allow an object to roll over a surface rather than allowing them to slide over the surface.
- This results in less Friction and hence the easy movement of the object.
- Rolling Friction is also used in the parts of machines that are moving continuously.
- In this way, the sliding Friction is removed with the help of rolling Friction, and therefore the adverse effects of Friction such as the production of heat or wear and tear of the mechanical parts are also reduced.
- For instance, ball bearings are being used in fans and bicycles to reduce Friction.
- Air, water, and other liquids collectively are called fluids. They also exert a Frictional force on the object that travels through them. Such a Friction is called fluid friction or drag. The amount of Frictional force by a fluid on an object depends upon the following:
- The speed of the object with respect to the fluid.
- The nature of the fluid, its viscosity, or its tendency to resist the flow.
- The shape of the object.
Fluid Friction comprises Internal and External Friction:
- Fluids comprise internal Friction that occurs between the molecules of a liquid as they are also in motion. The viscosity of a liquid, therefore, depends upon the internal Friction.
- An external Friction in fluids is the force exerted by the fluid on the object that flows through it.
- As an object travels in a fluid it loses its energy in order to overcome the fluid friction. Hence, things that can easily flow in fluids have special shapes.
- For instance, ships and boats have a particular shape that allows them to resist fluid Friction.
- Birds and airplanes have a specific shape that allows them to fly in the air.
- Fishes also have a specific shape such as a tail and fins that allow them to swim continuously in water and even prevent the loss of energy due to fluid Friction.
- Not only this, all the vehicles are designed in a way that they can resist fluid Friction because air is present everywhere.