How Does Friction Impact Automobile Safety and Performance?
What is Friction – A Brief Outline
Friction can be defined as a force that creates resistance between the relative motions of two objects in contact. It mainly takes place due to microscopic irregularities which are present on the surface of both objects. It means that rougher the surface; the greater will be the friction between two objects and vice versa.
Additionally, two main characteristics of friction are that it always takes place in the opposite direction of relative motion between two objects and parallel to the surface of contact. Besides, the use of friction in automobiles is one of its most essential functions in our daily lives.
How Does Friction Affect Cars?
Friction in the automobile aids it to move, turn corners or slow down when necessary.
The various advantages and disadvantages of friction in automobiles have been listed below –
When a car or any other automobile starts, its tyres push against the road. As a reaction, the friction present between the car and road pushes back which acts as a forward motion that enables a car to move forward.
Friction in the automobile also comes in handy when a car is taking a turn at the corner of a road. As friction present between the road and tyres, wheels ‘grab’ on to the ground and stay put. It prevents a car from sliding while turning a corner, which is why a car can sometimes skid or slide on a muddy or wet road as they have less friction than regular roads.
Apart from movement, friction in a car or automobile slows down. Disc brakes of cars have a steel disc attached to wheels which can be found between the two small brake pads. When the brakes are pressed, brake pads push the discs on the car wheels which cause friction. This slowed down the wheels and finally stopped the car.
Apart from friction on cars, it also works the same in the case of bicycles. When the brakes on bicycles are applied, brake pads press down on bicycle wheel rims. It causes friction and slows it down.
However, friction in automobiles also generates heat which accelerates wear and tear of a car engine. Furthermore, around one-third of a car’s fuel usage goes towards overcoming friction.
Advantages and Disadvantages of Friction
In our day to day lives, friction is a necessary evil. For instance, without it, we wouldn’t be able to walk properly. Like friction in automobiles, when we walk, we push the ground with our foot, and as an opposite reaction, the ground too pushes us back.
However, friction present between the road and sole of our shoe enables us to keep our grip and prevent slipping, which is why we tend to slip and fall on wet or well-polished surfaces.
Similarly, it is because of friction we can write and draw on surfaces like paper and blackboard. When we write, bits of lead and chalk break due to friction present between them and paper. These bits then cling to the surface and appear as writing or drawing.
Types of Friction
To better understand friction and cars, one should have a detailed idea of four main types of friction –
Static Friction
The frictional force that occurs between two objects when they are at rest is known as static friction. In this situation, acceleration can only take place when the force applied to the one object in rest can overcome the static friction. In other words, if there is no static friction, an object or body would continue to move. Examples of static friction include when a car is parked on a hill, a ball resting on the floor etc.
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Sliding Friction
Sliding friction acts on an object or body when it is motion. It is also known as kinetic friction. The resistance offered by sliding friction is weaker than static friction. It is because a body in motion stays in motion, whereas it is more difficult to overcome the static force and move an object.
Rolling Friction
The friction resisting movement of a rolling object or body is known as rolling friction. This type of friction has even lesser resistance than sliding and static friction which is one of the reasons it is easier to move a heavy object by rolling rather than by sliding.
Fluid Friction
The friction faced by an object or body when it is moving through a fluid medium is known as fluid friction. Examples include resistance faced by swimmers when swimming, Skydiver falling towards the ground using a parachute etc.
FAQs on Friction in Automobiles: Definition, Types & Real-Life Applications
1. What is friction in the context of an automobile?
In an automobile, friction is a force that resists motion between surfaces in contact. It is most critical between the tyres and the road, enabling the car to accelerate, brake, and steer. It also occurs in various components like the brake system, clutch, and within the engine, where it can be both useful and a source of energy loss.
2. How is friction essential for controlling a car's movement?
Friction is indispensable for vehicle control. Its key roles include:
Acceleration: The friction between the tyres and the road provides the grip needed for the wheels to push against the ground and move the car forward.
Braking: Brake pads press against the brake discs, creating friction that converts the car's kinetic energy into heat, slowing it down.
Steering: Friction provides the necessary centripetal force to allow the car to turn corners without skidding sideways.
3. What are the main types of friction that act on a car?
Several types of friction are at play in an automobile:
Static Friction: Acts on the tyres to get the car moving from rest and to prevent skidding during turns.
Rolling Friction: The resistance that occurs as the tyres deform while rolling on the road surface. This affects fuel efficiency.
Sliding (Kinetic) Friction: Occurs in the brake system and clutch plates when they are engaged.
Fluid Friction: Also known as air resistance or drag, this is the force the air exerts on the car's body as it moves.
4. Why is static friction, not kinetic friction, the primary force that moves a car forward?
This is a common point of confusion. The part of the tyre that touches the road is momentarily at rest relative to the ground. The engine makes the tyre push backward on the road, and in response, the force of static friction from the road pushes forward on the tyre, propelling the car. If the wheels were spinning out or skidding, it would be kinetic friction, which is weaker and results in a loss of control and less effective acceleration.
5. Where is friction a disadvantage in an automobile, and how is it reduced?
Friction is a disadvantage between moving parts inside the engine and gearbox. It causes:
Wear and Tear: It gradually erodes the surfaces of components like pistons and bearings.
Energy Loss: It converts useful mechanical energy into unwanted heat, reducing the car's overall fuel efficiency.
To mitigate this, lubricants like engine oil are used to create a thin film between surfaces, and ball bearings are used to replace sliding friction with much lower rolling friction.
6. How does the tread pattern on a tyre improve its grip on wet roads?
The primary function of a tyre's tread pattern is not to increase friction on dry surfaces but to manage water on wet ones. The grooves and channels in the tread are designed to expel water from beneath the tyre. This prevents a layer of water from building up, a dangerous phenomenon known as hydroplaning, which would cause a near-total loss of friction. By maintaining direct contact between the rubber and the road, the tread ensures reliable grip.
7. What is rolling friction and how does it affect a car's fuel efficiency?
Rolling friction is the resistive force that occurs because a tyre continuously deforms and reshapes as it rolls along a surface. This process requires energy, which is drawn from the engine. Therefore, higher rolling friction means the engine must work harder to maintain speed, leading to lower fuel efficiency. Properly inflated tyres and modern tyre compounds are designed to minimise this deformation and reduce rolling resistance.
8. Compare the role of friction when a car starts moving versus when it turns a corner.
While both actions rely on static friction, the direction and purpose of the force are different:
Starting Motion: Friction acts parallel to the wheels, in the forward direction of the car. It is a propulsive force that overcomes inertia.
Turning a Corner: Friction acts perpendicular to the car's direction of motion, pointing towards the centre of the turn. It acts as the centripetal force, preventing the car from continuing in a straight line and guiding it through the curve.
