All the concepts of waves that are required for A Level Physics in animation form and very interactive

Welcome to the animated are of this blog where learning becomes fun.
All the knowledge and stuff that you will need to learn in your A Levels when studying waves and their property and oscillations are presented below in a animated way.Learn and enjoy.

Ppa6 Concep Tests Ch 11

What are our main purposes for the use of satellites ?

1.To transmit telecommunication messages to and fro .
2.To get weather news.
3.To get photos of the solar system or other planets.
4.

Waves and vibrations:

Speed of a wave= frequency x wavelenght of the wave
period =1/frequency


Light waves and transverse waves and sound waves are longitudinal waves.

If you still need any more information, please leave a cooment.

A Level Physics :Vectors and thier addition with Force

The maximum value of a resultant force when two forces act on  a body = Force 1+ Force2
The minimum value of a resultant force when two forces act on a body=  Force1 - Force2

The resulatant force of two forces that act in many diverse direction.

Pressure

The physical equation for pressure is Pressure = force/are Pressure is measured in Pascals.

Below is a graphical explanation for pressure , please give me your views by commenting!

This picture was taken by me in karainagar with a digital camera and is protected by copyright.

when the force on a constant area increases the pressure also increases
When the area on which a constant force is applied decreases the pressure increases.

A Level Physics notes ans questions: Equation of continiuty

The equation of continuity says that the rate of mass flow through a given tube at the entrance and at the exist is the same, if there is no other way for the fliud to get out from the pipe. Lets put things into a simpler form :

A1 x V1= A1 x V1

Lets prove this equation:

Mass flow rate = mass flowing through the pipe in one second
                               = V x D /t (t=1 second)
                               = l x a x D  /t
                               = A x D x V ( l/t)
 Because the mass flow rate is constant from th equation of continiuty
A1 x V1 x D =  A2 x V2 x D

Equation of continuity and Bornoulllis law A Level Physics Notes Questions Answers  and Explanation

 As Density D is the same on both sides ,it gets canceled out.

So :,
A1 x V1 = A2 x V2

You must be able  to prove this equation , and using this equation you will be able to solve many problems in your A Level Physics exam paper.

For a set of questions and Answers onthis section of A Level Physics Please click here.

A Level Physics:Dynamics and Motion(formula and solved problems)

Dynamics Physics a level Motion in a srtraight line. Speed is different from velocity .Speed is the distance moved in a unit time , while velocity is the distance moved in a unit time in a particular direction. We can assume that a car is moving in a stright line with a velocity of 5 m/s ,than it is evident that the car travels a distance of 5m in one second without any change in direction, The equation which is used is: velocity = distance moved /time taken (use this formula in exams and when doing problems) Example: A motor bike travels 1000 m in 6 minutes,find the speed of the motor bike? (dear students take note of the wording please the question asks for the speed of the bike as it doesnot say that the bike travelling in a specific direction. If you have any further doubts about the specifications about the differenciations of speed and velocity and the problems involved in them please be kind enough either to email me at veeradinesh85@gmail.com or just leave a comment below.Any type of doubts are welcome even ifthey are not from this section.

A Level Notes: Law of Floatation

The principle of floatation says that for a floating objects,the weight of the object equals the upthhrust exerted by a fluid on that object.
ie: When a body floats in a liqiud , it is in equilibrium and is acted upon by two forces only,its weigght and the upthrust.

These two forces must be equal and opposite to satisfy the conditions of floatations,

 Weight of object = upthrust

But as we already know from Archimedes principle that U=Vx Dx g N..............................1


So hence,  Weight=VDg..........................2

With these two equations you must be able to solve problems on the law of flatation,

I wish you all the best in your exam.If you need any other notes or information in this topic or any other area of physics email me or simply put a comment.

Weights and Mass A Level Physics

The weight of an object is defined as the force acting on it due to the gravitational force .The weight of a object can be measured by attaching it to a spring balance and reading the scale.

But mass is differen in the way that it is equal to the density of the object multiplied by the volume of the object.
Mass is universally constant meaning it doesnot change from one planet to the other just as weight changes.

(a level revision,notes,syllabus,problems solved,help,tutorial)

Hydrostatics.
This is the study of fliuds and their behaviors.

Circular motion Physics A Level

Circular Motion

What is exactly meant by circular motion ? It is the physical motion of an object moving in a circular path about a center. There are circular motion in many areas of our life, for example the hour and minute hand of a clock displays circular motion, and also the planets and moons in the solar system show circular motion.(Although planets move in elliptical paths we consider them to be moving in circular paths for calculation purposes.)

First lets look at some important maths that are a essential for understanding todays topic of circular motion.

180 degrees = π radians 360 degrees = 2π radians 90 degrees   = ½ π radians For very small angles :     sin θ  = θ radians                                                        tan θ=  θ radians

* Ѡ (the angular velocity) is the angle in radians through which the the object in circular motion has turned in one second.

*ἀ (the angular acceleration) is the increase in the value of Ѡ (the angular velocity) per second.

* r –denotes the radius of the circle that we are dealing with.

The types of circular motion:

1.      Horizontal circular motion

2.      Vertical circular motion

3.      Conic pendulum

Different situation or means of circular motion:

1.      Revolving at a constant speed around a circle.(eg: hands of a clock)

2.      Revolving with variable speeds (that is with constant angular acceleration or constant angular deceleration)

*(eg : A car starts from rest and its wheels show constant angular acceleration)

1.   Constant speed circular motion:

A particle P revolves at a constant speed in a circular path. At time ( t=0), P is at P₁. After a time t , P is there as shown in the diagram. Consider the radius of the circular path to be r.

S=r θ  (θ in radians)

Velocity

 V=s/t

V=r θ/t  (from equation 1)

θ/t= Ѡ (angular speed)

Ѡ= θ/t

(linear velocity)  V= r Ѡ ( angular velocity)

Definition of angular speed:

The rate of change in angle is the angular speed.

The unit of angular speed is rad/s.

The Dimension of angular speed is T^-1

Angular speed is a scalar quantity because it has only a magnitude.

Angular velocity id a vector quantity ,because it has both direction and magnitude.

Rotation with a constant speed:

If a body is rotating with a constant speed then tangential acceleration is equal to zero.But still there an acceleration on the body toward the center. THIS IS CALLED CENTRIPETAL  ACCELERATION!

Errors and their types:

Errors can be grouped into two groups :
1 systematic error


 systematic: e.g. constant error (in all readings)
    cannot be eliminated by averaging
    error in measuring instrument B1
 
2.random errors
random: e.g. readings scattered (equally) about true value
    error due to observer
    can be eliminated by averaging
        (only if averaging not included for systematic


It is very to know these by heart as you will be given a direct question about errors in your physics AS exam.

Projectile motion A level Physics

Projectile motion is a special case of two dimensional motion with constant acceleration. Here, force due to gravity moderates linear motion of an object thrown at certain angle to the vertical direction. The resulting acceleration is a constant, which is always directed in vertically downward direction.
                                                         read the rest at http://cnx.org/content/m13837/latest/
Problems on Projectile motion can either start from the botom with an object thrown at a angle witha speed.or it can startfrom a height like a cliff with the object either thrown upward or horrizontally with an initial speed.Which ever the problem is about the following formulas can be used to tackle the questions..

Remember these formulas for doing problems on projectile motion:



The maximum Height that the particle has travelled = u2sin2o(theta)
                                                                       2g
 The time taken for the particle to  reach the ground again   = 2u sino
                                                                                       g
Range     = u2sin2o
                  g

Todays question: about Deriving a SI unit

 Expresse  the volt in terms of SI base units?

Ok lets get started:
We know that P=VxI
                             Fx d=VxI
       F is  kgm/s2  d is in m  and I is in A
So V= kgm2s-2A-1

If you need anymore help in deriving the SI units of other quantities just leave a comment and I shall reply.

Lets do a physics question (a level)

Lets do a physics question (a level)

welcome back

The question is as follows

Q:A laser emits light of wavelength 600 nm
. What is the distance, expressed as a number of wavelengths, travelled by the light in one second?

 We know that

 1 nm=10^-9m
 therefore:                           600nm =6 x 10^-7m

 we also know that the speed of light is= 3 x 10 ⁸m/s
 so v= f x L

 note that the question asks for the frequency

so: f= 3 x 10⁸/6 x 10^-7 Hz
 the answer is f= 5 x 10¹⁴ Hz

The important formulas and values that you must know for exams and to solve problems:

Please take note of the following because they will be useful in your exams: Click on the images to see them clearly!

Problem on circular motion - solved

the question:

An object of mass 4 kg moves round a circle of radius 6 m with a constant speed of 12 m/s.


Read the question first :

Calculate
1.the angular velocity
Answer: angular velocity= speed/readius
= 12/6
= 2 rad/s
ok this is done with the formula : angular velocity= speed/readius
the next question is
2.the force towards the center (using a=v2/r)

Answer: force = m a
= mx v2/r ok
= 4x 122/6
=96N

Rotational motion Physics A Level

Todays topic is rotational motion .

Many students take this chapter to be a difficult one, but in fact it is a very easy one :the only thing we will have to do is to compare rotational motion with linear motion and then do the questions based on the formulas we are going to derive:

Torque is considered as the force here and alpha that is angular acceleation is considered to be acceleration.

Torque is considered as the force here and alpha that is angular acceleation is considered to be acceleration

Torque= force x radius of circle

Rotational motion Physics A Level

Todays topic is rotational motion .

Many students take this chapter to be a difficult one, but in fact it is a very easy one :the only thing we will have to do is to compare rotational motion with linear motion and then do the questions based on the formulas we are going to derive:

Torque is considered as the force here and alpha that is angular acceleation is considered to be acceleration.

Torque is considered as the force here and alpha that is angular acceleation is considered to be acceleration

Torque= force x radius of circle

Free Fall

Free Fall

A body moving freely under gravity has a constant acceleration of 9.8 m/s2 downwards towards the centre of the earth. This can be proved by the following:
mg=ma (during free fall)
Here m gets cancelled out,
g=a
As we already know that the force gravity on 1 kg mass is 9.8 N ,therefore the acceleration of free fall is also 9.8 m/s2 .
It is evident from the following that a body moving freey under gravity , increases its speed by 9.8m/s every second.

Free Fall

Free Fall

A body moving freely under gravity has a constant acceleration of 9.8 m/s2 downwards towards the centre of the earth. This can be proved by the following:
mg=ma (during free fall)
Here m gets cancelled out,
g=a
As we already know that the force gravity on 1 kg mass is 9.8 N ,therefore the acceleration of free fall is also 9.8 m/s2 .
It is evident from the following that a body moving freey under gravity , increases its speed by 9.8m/s every second.

Physics A Level formulas for motion.

It is very advisable to study and learn the following formulas by heart:
v= s/t
a= v/t

The cambridge system of conducting a level physics exams

CIE provides a easy way to get a level physics qualification.
Either you can take the exam completely by doing 5 papers, or you can first do the AS/L which has 3 papers then do A2 in the second year which comprises of two exam papers.

SI units and modern physical measurements

 

 I am resuming to add notes to this blog after quite a few days.


Todays topic: Measurement and Analysis.
I would like to begin with an introduction about phyiscs.Physics is defined as putting the theories of nature into mesurements.


The SI unit of mass is kilogram (kg):


The modern mass unit that is a kilogram is is based on the mass of a platinum block placed in the french bereau of measurement.

The SI unit of distance is the meter (m):
This modern assumption of distance is based on the distance travelled by light waves in 1/300000000 second(that is 300 million time of a second)

The SI unit of time  is the second (s):

The modern value of a second is based on a specific number of oscillations pf a ceasium isotope.

The above details will not be tested in  depth at exams,but it is still vital for you to remember them because they will be of great help in understanding to solve problems.

What's the rate of change dm/dt of the mass m(t)?

Gas moves out of a pipe at a rate of v m/s which has a cross-sectional area of A .The density of the gas is p.


Our task is to prove that dm/dt=pAv

 OK lets begin with enthusiasm:


p(density) =mass/volume (we learnes this equation in a lower class)


therefore mass=density x volume


ie m = pV


we already know that volume= area x height 


we already know that height= velocity x time




therefore mass   = density x volume
                           =density x area x height
                           =density x area x velocity x time
                           = p x A x v x t


Therefore dm/dt =p x A x v


THE RATE OF CHANGE IN MASS IS EQUAL TO THE DENSITY TIMES THE CROSS SECTIIONAL AREA TIMES THE VELOCITY .

The law of conservation of momentum

This law states that momentum is neither created nor destroyed in a collision or whatever the case may be.

Momentum change and force.

Momentum:




Newtons first law:  A body will continue in a state of rest or in uniform motion unless an external force acts on it .
So it is evident from this law that we have to appply external forces to make the body move,and also we have to provide external forces to bring a body to rest or to increase the speed of the body.
Newtons second law: The rate of change of momentum is directly proportional to the force applied.
   
The equation derived from this important law  is :   force=   change in momentum
                                                                                                       change in time

As we also know the equation for momentum which is
   
  momentum = mass X velocity

Vectors and Scalars

Displacement and velocity are examples of vectors because they have a magntude and a direction .To make things simpler lets put this is simple terms.

The properties of vectors are:
1.they have a magnitude
2.they have a direction( only vector quantities ahve direction)


Distance and speed are examples of scalers Such quantities have only a magnitude and no direction.

Whether it is O/L or A/L You need to differenciate and identify scalers and vectors which are important parts of basic physics.
You will be tested in exams asking you to say whether a given quantity is a vector or a scaler.



If you have any further doubts about the specifications about the differenciations of speed and velocity and the problems involved in them please be kind enough either to email me at veeradinesh85@gmail.com or just leave a comment below.Any type of doubts are welcome even ifthey are not from this section.

Speed and velocity

Dynamics Physics a level

Motion in a srtraight line.
Speed is different from velocity .Speed is the distance moved in a unit time , while velocity is the distance moved in a unit time in a particular direction.
We can assume that a car is moving in a stright line with a velocity of 5 m/s ,than it is evident that the car travels a distance of 5m in one second without any change in direction,

The equation which is used is:  velocity = distance moved /time taken (use this formula in exams and when doing problems)

Example: A motor bike  travels 1000 m in 6 minutes,find the speed of the motor bike? (dear students take note of the wording please the question asks for the speed of the bike as it doesnot say that the bike travelling in a specific direction.

If you have any further doubts about the specifications about the differenciations of speed and velocity and the problems involved in them please be kind enough either to email me at veeradinesh85@gmail.com or just leave a comment below.Any type of doubts are welcome even ifthey are not from this section.