Class-9 Physics CBSE

Physics Concept Maps Class IX • Motion • Force and Law of Motion • Gravitation • Fluid • Work, Energy & Power • Wave Motion and Sound

Rest

Motion When object changes it position with respect to time

When object changes it position with respect to time

Scalar : depend only on magnitude A

Physical Quantities Vector : Depend on magnitude and directions

Distance

O

path-1

Scalar quantity ; S.I. unit metre

A

B

path-2

Vector quantity ; S.I. unit metre

Displacement

B

Y Speed

Average speed

Velocity

A

Scalar quantity ; S.I. unit metre per second

uniform speed

Non-uniform speed

Instantaneous speed

Vector quantity ; S.I. unit metre per second

Average Velocity uniform Velocity

O

X

Time

Non-uniform Velocity Instantaneous Velocity

Y A Acceleration

Vector quantity ; S.I. unit metre per second square

a=v–u t Positive Acceleration

Negative Acceleration

O Equations of motion

v = u + at

2

s = ut + 1/2at

2

2

v – u = 2as

Time

X

Force Force is push or pull acting on an object Formula

F=m×a Where m= mass a=acceleration Force is applied to change the shape of an object

Effect of force

Force is applied to move an object from the position of rest Force is applied to change the speed of motion To change the direction of motion

CGS:-gcms

-2

Units of force -2

SI:-kgms or newton Inertia of rest

Inertia of motion Law of Inertia Inertia of direction Newton's laws of motion Rate of change of momentum is force

Every action has equal and opposite reaction

Momentum : Momentum is product of mass and velocity

CGS:-gcms

-1

Units of momentum SI:-kgms

-1

Impulse : Impulse is product of time and force

Units of Impulse

kg metre per second

direction of particles vibration

Wave Motion

Mechanical waves

Longitudinal waves

Non mechanicalwaves

Transeverse waves direction of wave propagation Transeverse waves

sound

Sound is a form of energy which is produced by a vibrating body. It travels in the fom of waves

Propagation of sound : Sound transmitted in the form ofmechanical Waves.Thus sound needs amedium to travel Wave length(l) It is the distance between two consecutive compressions or rarefractions.

Terminologies

C=region of max. density R=region of min. density C

R

C

R

C

R

C

Amplitude (a) The maximum displacement of vibrating body is known as amplitude Frequency (u) The number of oscillations produced per second. It is measured in hertz (Hz). The speed of sound wave is given by speed =frequency × wavelength. Time period Time taken to complete

one vibration Wave velocity: Distance travelled in one vibration

Loudness or Softness Terminologies related to sound Pitch

Timber or Quality

Range of Hearing : 20Hz-20KHz less than 20Hz : Infrasonic sound or infra sound More than 20 Hz : Ultrasonic sound or ultra sound Ultrasound : Produced by quartz crystal oscillator

High frequency, small wavelength and high energy content

Reflection of sound

Echo

obstacle

Sonar

clap Transmitter

echo

sound waves

Receiver

Bottom of sea