What is physics ?A science that deals with matter,energy and

their interactions.

Physics

What is motion ?Any body which is moving or is not at rest is

known as the body is in motion...

The basic knowledge of physics starts up with

Motion.......

Types of motion...• Rectilinear motion: An object moving in straight line.

• Curvilinear motion: A body moving along a curved path.

• Rotatory motion: An object moving around a fixed point.

• Oscillatory motion: The to and fro motion of an object like pendulum of the clock.

• Vibratory motion: The motion of the sitar string when plucked exhibits vibratory motion.

• Multiple motion: When an object possesses two or more type of motion at same time.

Let us start up with some important S.I units of the terms used in motion at the level of

9th grade...•What is S.I unit ? S.I unit refers to the international system unit..

• Speed: meter per seconds.

• Velocity: meter per second.

• Acceleration: meter per second square.

• Distance: kilometer per hour.

There are some simple terms of physics which are important to be

told.......• Distance: The proper length of path covered by an object with

respect to time is known as distance.

• Displacement: The shortest length of path between initial and final position is known as displacement.

• Speed: Distance Time

• Velocity: The rate of change of displacement is known as velocity.• Acceleration: The uniform rate of increasing speed of the body is known as acceleration ( it can be zero or positive and negative ).

• Retardation: Negative acceleration by an body refers to the body at retardation mode.

• Reference point: The location of an object is described by specifying its reference point. The point from which location is observed and measured is called the reference point. The reference point is also known as origin.

• Rest: If an object does not changes it's position with respect to time and the fixed reference point or origin taken by us it is called as the body is at Rest.

• Uniform speed: When an object covers equal distance in equal interval of time the speed of the body is known meant as uniform speed.

• Non-uniform speed: When an object does not covers equal distance in equal interval of time the speed of the body is known as non-uniform speed.

• Scalar quantity: A physical quantity which is described completely by its magnitude is called as Scalar quantity.

• Vector quantity: A physical quantity which is described completely by its magnitude as well as with direction is called as vector quantity.

Distance and displacement

explanation.....

A B

C

D

EHere in this figure from point A to E is Distance

travelled and from point A to B it is Displacement.

Their are three important equations of motion...

• v= u + at. ( here v represents final velocity, u initial velocity,a acceleration and t time.

• s= ut + 1/2 at2 ( here s represents

displacement but it is equal to distance in 2d )• V + u = 2as22

In recent slide we read about the three different types of equation of motion......now let us solve

some questions based on these equation of motion......

• Calculate the height of the body when it takes 4 seconds to reach at top ?

• Ans. we have t = 4.

• We have third equation of motion. S = ut + 1/2 at

• S = 0*4 +1/2* 9.8*16

• S = 0 + 4.9*16

• S = 78.4

• The height attained by the body is 78.4 m.

2

( 9.8 m/s is the fore of gravity of the earth )

Calculate the velocity of the body when it is thrown vertically in upward direction and

takes 2 sec to reach at top?

• We have 1st equation v= u + at.

• v = 0 + 9.8*2

• v = 19.6

• Final velocity is 19.6 m.

We solve some questions based on these equations of

motion...Now let us learn about some facts based on motion...

• Generally there is always zero displacement of the body moving on circular track

• The diameter of the circle is the displacement of the body traveling around it.

The endThank you for watching

Created by: Abhinav Aggarwal