COURSES ON HS PHYSICS AND JOINT ENTRANCE{ JEE AND NEET}

VECTORS AND SCALARS Certain physical quantities described by a numerical value alone (with units specified) and are added according to the ordinary are completely rules of algebra. As an example the mass of a systemn is described by saying that it is 5 kg. If two bodies one having a mass of 5 kg and the other having a mass of 2 kg are added together tè o make a composite system, the total mass of the system becomes 5 kg + 2 kgg = 7 kg. Such quantities are called scalars. 2 kg The complete description of certain physical quantities requires a numerical value (with units specified) as well as a direction in space. Velocity of a particle is an example of this kind. The magnitude of velocity is represented by a number such as 5 m/s and tells us how fast a particle is moving. But the description of velocity becomes complete only when the direction of velocity is also specified. We can represent this velocity by drawing a line parallel to the velocity and putting an arrow showing the directi...

  units of measurements in physics units of measurement class 11 units of measurements are units of measurements all a unit of measurement accepted universally Fundamental and Derived Units The exact specification of the measurement of a physical quantity requires (i) the standard or unit in which the quantity is measured. (ii) the numerical value representing the number of times the quantity contains that unit The physical quantities which do not depend upon other quantities are called fundanental quantities. In M.K.S. system the fundamental quantities are mass, length and time, while in more general standard Internationl (S.I.) system the Fundamental quanti length, time, temperature, ties are mass, illuminating power (or luminous intensity), cur rent and amount of substance. The units of funda- mental quantities are called fundamental units.  The units of physical quantities which may be derived from fundamental units are called derived units. 2. Systems of Units There are f...