دانلود کتاب مقاهیم فیزیک – بخش اول

The nature around us is colourful and diverse. Itcontains phenomena of large varieties. The winds, thesands, the waters, the planets, the rainbow, heating ofobjects on rubbing, the function of a human body, theenergy coming from the sun and the nucleus ¼¼ thereare a large number of objects and events taking placearound us.Physics is the study of nature and its laws. Weexpect that all these different events in nature takeplace according to some basic laws and revealing theselaws of nature from the observed events is physics. Forexample, the orbiting of the moon around the earth,falling of an apple from a tree and tides in a sea on afull moon night can all be explained if we know theNewton’s law of gravitation and Newton’s laws ofmotion. Physics is concerned with the basic ruleswhich are applicable to all domains of life.Understanding of physics, therefore, leads toapplications in many fields including bio and medicalsciences.The great physicist Dr R. P. Feynman has given awonderful description of what is “understanding thenature”. Suppose we do not know the rules of chessbut are allowed to watch the moves of the players. Ifwe watch the game for a long time, we may make outsome of the rules. With the knowledge of these ruleswe may try to understand why a player played aparticular move. However, this may be a very difficulttask. Even if we know all the rules of chess, it is notso simple to understand all the complications of a gamein a given situation and predict the correct move.Knowing the basic rules is, however, the minimumrequirement if any progress is to be made.One may guess at a wrong rule by partiallywatching the game. The experienced player may makeuse of a rule for the first time and the observer of thegame may get surprised. Because of the new movesome of the rules guessed at may prove to be wrongand the observer will frame new rules.