KINEMATICSLINEAR MOTION

Terminology in Kinematics1. Linear motion – means is a motion along a straight line.

2. Distance – is the length of the path taken irrespectively of its direction of motion.3. Distance is a scalar quantity.4. Displacement – is the distance moved in a specific direction and its magnitude depends on its initial and final positions. Not depend on the path taken by the object.4. Displacement is a vector quantity. SI unit in metre , m5. Speed is the rate change of distance travelled. SI unit of speed is ms – 1 .

6. Velocity is the rate change of displacement. SI unit of velocity is ms – 1 .7. Speed is a scalar quantity .8. Velocity is vector quantity.9. Instantaneous Velocity is its velocity at a particular instant. Calculation for this is

dtdsv

Terminology in Kinematics10. Uniform velocity – the magnitude and the direction of the velocity do not change.

11. Instantaneous speed – the differential rate of distance travelled.

12. Average velocity = change in displacement/ total time taken.

13.Average speed = Total distance travelled/ Total time taken.

14. Acceleration = Change in velocity/Time taken

15. Acceleration is a vector quantity.

16. An object is said to undergo acceleration if:

a. The magnitudes of its velocity changes. b. The direction of the motion is changing. Especially in circular motion.c. Both the direction and magnitude of the velocity are changing.

tsvav

17. Instantaneous acceleration is the differential rate of change of velocity.

dtdva

Example:

Final point

Initial point

Final point

Initial point

Final point

Initial point

LINEAR MOTIONEQUATION OF MOTION 1

EQUATION 1

EQUATION 2

VERTICAL MOTION UNDER GRAVITY

PROJECTILES MOTION

PROJECTILES: THROWING HORIZONTALLY

How does its motion change with speed?Ans: As speed increases, the ball travels horizontally, but its vertical motion is unaffected.

Does the ball take longer to reach the ground when it is thrown faster?Ans: No, it takes the same time, no matter what its horizontal speed.

How does the horizontal distance travelled by the ball d on depends on its initial velocity?Ans: Horizontal distance travelled is proportional to initial velocity, s = ut.

EXAMPLES FOR OBJECT THROWING HORIZONTALLY

Example:

PROJECTILE MOTION

Ans: 450 gives the greatest range .

EXAMPLES FOR OBJECT MOVING IN PROJECTILE MOTION

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