IX A Science Ch-MOTION
DATE 21/6/21
Class IX
Chapter Motion
An object is said to be in motion when its position changes with time.
We describe the location of an object by specifying a reference point. Motion is relative. The total path covered by an object is said to be the distance travelled by it.
The shortest path/distance measured from the initial to the final position of an object is known as the displacement.
Uniform motion: When an object covers equal distances in equal intervals of time, it is said to be in uniform motion.
Non-uniform motion: Motions where objects cover unequal distances in equal intervals of time.
Speed: The distance travelled by an object in unit time is referred to as speed. Its unit is m/s.
Average speed: For non-uniform motion, the average speed of an object is obtained by dividing the total distance travelled by an object by the total time taken.
Velocity: Velocity is the speed of an object moving indefinite direction. S.I. unit is m/s.
Acceleration: Change in the velocity of an object per unit time.
Homework- Write down formula for velocity, Acceleration and Speed.
Date 24 / 6/21
Class IX
CHAPTER - MOTION
Speed: The distance travelled by an object in unit time is referred to as speed. Its unit is m/s.
Average speed: For non-uniform motion, the average speed of an object is obtained by dividing the total distance travelled by an object by the total time taken.
Velocity: Velocity is the speed of an object moving indefinite direction. S.I. unit is m/s.
Graphical representation of motions
(i) Distance-time graph
For a distance-time graph, time is taken on x-axis and distance is taken on the y-axis.
[Note: All independent quantities are taken along the x-axis and dependent quantities are taken along the y-axis.]
Homework- A scooter travelling at 10 m/s speed up to 20 m/s in 4 sec. Find the acceleration of scooter. Solve it.