Chapter 8 Motion

OUR CONCEPTS

Facts that Matter

•   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 in definite direction. S.I. unit is m/s.

•   Acceleration: Change in the velocity of an object per unit time.