Physic Tutorials

In this piece, I will discuss the advantages and disadvantages of friction. When a person walks along a road, he or she is prevented from slipping by the force of friction at the ground. Also, when a solid is in contact with another, the roughness of their surfaces prevent them from sliding freely over one another.

## What is Friction

Friction is defined as a force which acts at the surface of separation between two objects in contact and tend to oppose the motion of one over the other. This does not appear unless there is a relative motion or a force tending to produce motion

The laws of friction are stated below

• The frictional force between two surfaces opposes their relative motion
• The frictional force is independent of the area of contact of the given surfaces when the normal reaction is constant
• The limiting frictional force is proportional to the normal reaction for the case of a static friction

Types of Friction

There are two types of friction; they are:

1. The static or limiting friction
2. The kinetic or dynamic friction

The limiting friction is that which exists between two surfaces when one is about to move relative to the other while

The kinetic friction is the friction that exists between two surfaces moving relative to each other with a constant speed.

Friction depends on:

1. The nature of the surfaces in contact e.g. as rough smooth, polished, wet, dry.
2. It varies directly with the normal force pressing the surface together. F = NR

Some of the uses of friction are:

1. It enables the brakes to stop the car and locomotive to pull the train.
2. Friction helps us to walk, friction between our feet and the ground assists us to walk without slipping.
3. Friction makes gripping object possible.
4. It helps in the rotation of the various parts of the machine.
5. The ladder stays on the wall without slipping or skidding because friction between the ladder.
6. It is used in grindstone to sharpen knives and chisels
7. It enables a screw or a nail in place after being screwed into a position
8. It is utilized in fan belts used over wheels or pulleys in machinery

1. Friction causes wear and tear of machines and engine parts as they rub each other.
2. It reduces the efficiency of a machine. It wastes useful energy by converting them to heat.
3. It reduces motion.
4. It causes the heating of engines. This is because the energy which must be used to overcome friction is converted into heat.

## Methods of Reducing Friction

• Three ways of reducing friction are:
• The use of lubricants like oil, grease, air, and graphite
• The use of ball or roller bearings
• The streamlining of body shapes of moving objects

### Bolarinwa Olajire

A tutor with demonstrated history of working in the education industry. Skilled in analytical skills. Strong education professional with a M. SC focused in condensed matter.