The forces which we see in our day to day life like muscular, friction, forces due to compression and elongation of springs and strings, fluid and gas pressure, electric, magnetic, interatomic and intermolecular forces are derived forces as their originations are due to a few fundamental forces in nature.

A few fundamental forces are:

1. Gravitational Force: It is the force of mutual attraction between any two objects by virtue of their masses. It is a universal force as every object experiences this force due to every other object in the universe.
2. Electromagnetic Force: It is the force between charged particles. Charges at rest have electric attraction (between unlike charges) and repulsion (between like charges). Charges in motion produce magnetic force. Together they are called Electromagnetic Force.
3. Strong Nuclear Force: It is the attractive force between protons and neutrons in a nucleus.It is charge-independent and acts equally between a proton and a proton, a neutron and a neutron, and a proton and a neutron. Recent discoveries show that protons and neutrons are built of elementary particles, quarks.
4. Weak Nuclear Force: This force appears only in certain nuclear processes such as the β-decay of a nucleus. In β-decay, the nucleus emits an electron and an uncharged particle called neutrino.This particle was first predicted by Wolfgang Pauli in 1931.

The qualitative characteristics of accounting information are as follows:

1. Reliability : It means the accounting information must be reliable i.e., the users must be able to depend on the information. It must be factual and verifiable. A reliable information should be free from errors and bias.
   To ensure reliability, the information disclosed must be credible, verifiable by independent parties, must use the same method of measuring and be neutral and faithful.
2. Relevance : Accounting information presented by financial statements must be relevant to the decision making needs of the users. It means Unnecessary and irrelevant information should not be included. To be relevant, the information must be available on time, must help in prediction and feedback, and must influence the decisions of users.
3. Understandability : It implies that the information provided in the financial statements must be prepared in such a manner that it is understandable by the its users. Understandability implies that the accounting information provided to the decision-makers must be interpreted by them in the same sense as it was prepared and conveyed to them. This can be done by giving proper explanatory and working notes to explain the information.
4. Comparability : It means that the users should be able to compare the accounting information. To be comparable, accounting reports must belong to a common period and use common unit of measurement and format of reporting.
    

Australopithecus were the first to use tools. About 35,000 years ago, we came across the evidence of are markable improvement in the method of hunting animals. It became clear from the event that a special type of spear was used to hunt animals. The tools used by early man can be categorised into three types. They are discussed under following heads:

1. Hand-axes: They were used for pouncing. In the beginning, they were used without a handle, but later on wooden handle was attached to it. It was made possible to use them with much force.
2. Chopper: They were made of heavy stones worked to a sharp edge in one direction only, and were most probably used for chopping meat.
3. Flake implements: They were used as knives and scrapers for finer works. For thousands of years of man’s early history the only remains that we find are crude stone tools. These tools are often found lying along the terraces of rivers, or in the huts or caves where early man used to live and roam in search of wild animals. These tools made by him served many purposes such as skimming of dead animals. cutting their flesh, etc.

About 35,000 years ago new kinds of tools such as spear throwers, bow and arrow came into being

EVOLUTION OF THE EARTH

1. The earth was initially barren rocky and hot Object
2. Hydrogen and helium were present
3. It was formed about 4.6 by a the earth was Layered structure
4. Lighter layer is formed at the outer surface
5. Density increase to wards inside the core

1 kilometer/hour [km/h] = 27.7777777777778 centimeter/second [cm/s]