KINEMATICS WHAT IS KINEMATICS The branch of mechanics

KINEMATICS

WHAT IS KINEMATICS The branch of mechanics concerned with the motion of objects without reference to the forces which cause the motion.

MOTION A body is said to be at motion if it changes its position with respect to a fixed point taken as a reference point in its surroundings with the passage of time.

REST A body is said to be at rest if it is stationary with respect to a fixed point taken as a reference point in its surrounding with the passage of time.

TYPES OF MOTION 1) Rectilinear motion 2) Curvilinear motion 3) Rotatory motion 4) Oscillatory motion 5) Vibratory motion

RECTILINEAR MOTION AN OBJECT MOVING ALONG A STRAIGHT PATH. EXAMPLE: A CAR MOVING ON A STRAIGHT ROAD.

CURVILINEAR MOTION AN OBJECT MOVING ALONG A CURVED PATH. EXAMPLE: A JAVELIN OR SHOT-PUT THROWN.

ROTATORY MOTION An object moving around a fixed point. Example: The Earth rotating on its axis.

OSCILLATORY MOTION The to and fro movement of an object about the mean position. Example: a simple pendulum.

VIBRATORY MOTION When an object moves to and fro at its stationary position its called vibratory motion. Example: Striking a Tuning fork.

MECHANICS The branch of physics that deals with the study of motion of objects and their response to force is called mechanics.

VECTOR A physical quantity which is described completely by its magnitude and direction is called vector quantity. Example: force, acceleration, velocity, displacement, momentum. Vector is represented by An → over the Unit

SCALAR A physical quantity which is completely described by its magnitude is called scalar quantity. Example: 1) Length 2) Time 3) Density 4) Speed 5) Distance

DISTANCE The actual length of the path traveled by a moving body in a given perriod of time is called the distance traveled by the body. It’s a scalar quantity and its value can never be zero or negative.

DISPLACEMENT It’s the shortest distance measured between the initial and final position. It’s a vector quantity.

ZERO DISPLACEMENT Can an object have zero displacement? Yes. An object can have zero displacement if it comes back to its original position. If initial position = final position or if the initial and final position lie on the same plane.

VELOCITY It’s the distance traveled by a body per unit time in a definite direction. It’s a vector quantity. SI unit is m/s. V = Distance traveled in a definite direction by time

SPEED The speed of a body is the distance traveled by the body in unit time. It’s a scalar quantity. Speed = distance / time 1 Kmph = 5/18 m/s

UNIFORM MOTION A body is said to have uniform motion if it travels equal distances in equal intervals of time. Example: movement of clock hands.

NON - UNIFORM MOTION A body is said to have non – uniform motion if it travels unequal distances in equal intervals of time. Example: A car traveling on uneven surfaces and changing speeds.

GRAPHICAL REPRESENTATION Uniform motion non – uniform motion

AVERAGE SPEED The average speed of a body is the total distance traveled by the body divided by the total time taken to cover the distance traveled. Average speed = total distance traveled/ total time taken

AVERAGE VELOCITY When the velocity of a moving body is changing continuously at a uniform rate, then the average velocity is given by the mean of initial (U) and final (V) velocities for a given period of time. Av = u + v /2 AV = displacement / time

UNIFORM VELOCITY A body has uniform velocity if it covers equal distances in equal intervals of time in a particular direction, however small these intervals may be. Example: a car moving in constant speed towards north at a constant speed.

VARIABLE VELOCITY A body is said to have variable velocity if : It covers unequal distances in equal intervals of time in a particular direction. Or If it covers equal distances in equal intervals of time but its direction keeps changing. Example: Blades of a fan, Car moving in a crowded road.

ACCELERATION It’s the rate of change of velocity of a body with respect to time. The SI unit is m/s 2 A=v–u/t, Where A = Acceleration v = Final velocity u = Initial velocity t = Time

NEGATIVE ACCELERATION When the velocity of a body decreases with time, its acceleration is negative. It’s also called retardation or deceleration. Example: A car applying brakes and slowing down.

Thank you Reuben Vinod