VIDHYAKSHETHRA

Vectors : A vector quantity is a quantity that has both a magnitude and a direction and obeys the triangle law of addition or equivalently the parallelogram law of addition. A vector is specified by giving its magnitude by a number and its direction. Some physical quantities that are represented by vectors are displacement, velocity, acceleration and force.  Position Vector :  It is a straight line having one end fixed to a body and the other end attached to a moving point and used to describe the position of the point relative to the body. As the point moves, the position vector will change in length or in direction or in both length and direction.  Displacement Vector :  Displacement vector is the straight line joining the initial and final positions and does not depend on the actual path undertaken by the object between the two positions. The magnitude of displacement is either less or equal to the path length of an object between two points.  ...

Rectilinear Motion : Motion is a change in position an object with time. Motion of an object along a straight line is called rectilinear motion. eg. Motion of a car along a straight road. Average Velocity :  Average velocity is defined as the change in position or displacement (Δx) divided by the time intervals (Δt), in which the displacement occurs. The average velocity can be positive or negative depending upon the sign of the displacement. It is zero if the displacement is zero.  Average Speed :  Average speed is defined as the total path length travelled divided by the total time interval during which the motion has taken place. Average speed is always positive since it does not tell the direction of motion.  Instantaneous Velocity & Speed :  Instantaneous velocity describes how fast an object is moving at different instants of time in a given time interval. It is also defined as average velocity for an infinitely small time...

⇃ Significant Figures :  In case of a measured value of a physical quantity the reliable digits plus the first uncertain digit are known as significant digits or significant figures. Significant figures indicates the precision of measurement. A choice of change of different units does not change the number of significant digits or figures in a measurement. Rules for Finding Significant digits All the non - zero digits are significant. All the zeros between two non-zero digits are significant, no matter where the decimal point is, if at all. eg. 2003.25 has got 6 significant figures. If the number is less than 1, the zero(s) on the right of decimal point but to the left of the first non-zero digit are not significant. In 0. 00 2308, the underlined zeroes are not significant. The terminal or trailing zero(s) in a number without a decimal point are not significant. eg. 123m = 12300cm = 123000mm has only 3 significant figures. The trailing zero(s) in a number with a deci...

Measurement : The comparison of any physical quantity with its standard unit is called measurement. Unit : The unit of a physical quantity is an arbitrarily chosen standard which is widely accepted by the society and in terms of which other quantities of similar nature may be measured.  Fundamental Physical Quantity/Unit : It is an elementary physical quantity, which doesn't require any other physical quantity to express it. eg. Unit of length, mass, time etc.  Derived Physical Quantity/Unit : They are formed by combination of two or more fundamental physical quantities or units. eg. Unit of velocity, acceleration, Force, Work etc. Systems of units CGS system :    The centimetre–gram–second  system  of units is a variant of the metric  system  based on the centimetre as the  unit  of length, the gram as the  unit  of mass, and the second as the  unit  of time. MKS System :   The...

Science : Science is a systematic attempt to understand natural phenomena in as much detail and depth as possible, and use the knowledge so gained to predict, modify and control phenomena. Steps involved in a scientific method Systematic Observations : This is the first step involved in any scientific method. In this, observations are made regarding various phenomenon happening in the universe and questions are raised about them. Sometimes a hypothesis about the phenomenon is also formed during this stage. Controlled Experiments : A controlled experiment is one in which everything is held constant except for one variable. Usually a set of data is taken for a control group, which is commonly the normal or usual state, and one or more other groups are examined, where all conditions are identical to the control group and each other except this variable. Sometimes it's necessary to change more than one variable, but all of the experimental conditions will be controlled...