NOTES ON ---- CHAPTER-8- MOTION(PART-1) CLASS-9 SUB-SCIENCE

on

Chapter - 8 (Motion)

SUB - Science

                                            Class- 9









MOTION:- The object change its position with respect to time, this process is known  as Motion.

MOTION ALONG STRAIGHT LINE:-

When object move in straight line without changing its direction is known as motion in straight line, it is also known as simple motion. Due to linear motion it's also known as One Dimension Motion.


UNIFORM MOTION:- A body is said to be in uniform motion if it travels equaL distance  in equal intervals of time.

Example:- A car travel 50 km in 1 hour and next in one hour it travels 50 km. That means car travels 100km in 2hours.


NON UNIFORM MOTION:- A body is said to be non-uniform motion if it travelles unequal distances in equal interval of time.

Example:-A car travel 50 km in 1hour
and next in one hour it travels 40 km. That means car travels 90km in 2 hours.


SPEED:- The rate of change of distance with respect to time is known as Speed.

Speed is scalar quantity that means it has only magnitude.
S.I. unit of speed is metre per second (m/s).
Formula for speed-
           Speed = Distance/time
     OR
            s = d/t

Average speed:- Average speed is Ratio between total distance travelled by object to the total time taken.

                         AS = Total distance travelled/Total time taken

VELOCITY:- The movement of object with direction is known as Velocity. It is also known as speed with direction.

Velocity is a vector quantity that means it has magnitude and direction.The S.I. unit is kilometre per hour(km/h).
                              Velocity = Distance/Time

                                    Or       v = s/t

                                                         s = total distance
                                                          t= time


Average Velocity:Average velocity is the  sum of initial velocity and final velocity divided by two.

                              Average Velocity = (initial velocity+final velocity)/2

                                                                  

ACCELERATION:-The rate of change of velocity per unit time is known as acceleration. That is-

                                 Acceleration =  change in velocity/time taken


    If the initial velocity is u and final velocity is v then the formula is -
                 a = (v - u)/t



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