Saturday, May 30, 2009

IIT 2011 June Study Plan

You can enjoy 31st May as a break.


June 2009

3. Atomic Structure

4. Classification of Elements and Periodicity in Properties


June 2009
5. Complex numbers XI

6. Sequences and series XI


June 1 to 10

4. The forces

The force chapter is a small chapter. It is indicated in detailed study plan that you can use 7th June to 20th June to revise chapters 1 to 4. Don't waste time. Use the scheduled time to revise all the difficult problems in the four chapters. By revising difficult problems, you will understand the logic of solving those problems. Read the concepts once again. Understanding and frequent recollecting the materials will make it easy for you in the future. Try to do new problems whenever you have time. In the examination, you may not get the problems that you have solved. But solving many problems will give you the confidence and you can solve the new problems given in the examination. You should not fear the new problem. You become capable of solving new problems by solving a large variety of problems.

June 11 to 20

5. Newton’s law of motion

June 21 to 30

6. Friction

Tuesday, May 26, 2009

IIT JEE 2009 Toppers - Planned Schedule is the Key

According to Times India Report dated 26.5.2009, Nitin Jain, the topper said planned schedule is the key to do well in any competitive examination. Listening to tutors and following it up diligently is the trick.

Friday, May 22, 2009

IIT JEE 2011 Physics Study Diary - Ch.3 Rest and Motion - Day 5

Rest and Motion
Day 5 May 25 2009 study plan

3.9 Change of frame
Ex. 3.10, 3.11
WOE 16,17, 18

Points to Note

The main theme of the section is expressing velocity w.r.t. one Frame into velocity w.r.t. to a different frame

If XOY is one frame called S and X'O'Y' is another frame called S' we can express velocity of a body B w.r.t. S as a combination of velocity of body w.r.t. to S' and velocity of S' w.r.t to S.

V(B,S) = V(B,S')+V(S',S)

V(B,S) = velocity of body w.r.t to S
V(B,S') = velocity of body w.r.t to S'
V(S',S) = velocity of S' w.r.t to S

we can rewrite above equation as

V(B,S') = V(B,S)- V(S',S)

We can interpret the above equation in terms of two bodies. Assume S', and B are two bodies. If we know velocities of two bodies with respect to a common frame (in this case S)we can find the velocity of one body with respect to the other body (V(B,S')

The above expressions for velocity were derived from the relation between position vectors of the body w.r.t. to S and S' and position vector of origin of S' with respect to origin of S.

r(B,S) = r(B,S')+r(S',S)

Differentiating the position vectors with respect to gives respective velocity

Formulas covered in the session

26. r(B,S) = r(B,S')+r(S',S)


r(B,S) = Position vector
r(B,S') = Position vector
r(S',S) = Position vector

27. V(B,S) = V(B,S')+V(S',S)

V(B,S) = velocity of body wrt to S)
V(B,S') = velocity of body wrt to S')
V(S',S) = velocity of S' wrt to S)

we can rewrite above equation as

28. V(B,S') = V(B,S)- V(S',S)

An Intersting Quote from Mark Twain

Yesterday I saw an interesting quote from Mark Twain

I do not allow my schooling to interfere with my education.

This may apply to JEE coaching. If you feel, you are not getting adequate inputs, you have to put in your efforts. Finally, you want a seat in the best institute not they.

So do not allow your coaching institute to spoil your education. Depend on them to a large extent, but listen to your judgement regarding your time table.

IIT JEE Physics Study Diary - Rest and Motion - Day 4

Day 4 - Study Plan

3.7 Motion in a plane
Ex. 3.8
3.8 Projectile motion
Ex. 3.9
WOE 11,12, 14

Points to Note

Motion in a plane

Motion in plane is described by x coordinate and y coordinate, if we choose X-Y plane. You can imagine time t is on the third axis.

The position of the particle or the body can be described by x and y coordinates.

r = xi = yj

Displacement during time period t to t+Δt can be represented by Δr

Δr = Δxi = Δyj

Then Δr/Δt = (Δx/Δt)i = (Δy/Δt)j

Taking the limits as Δt tends to zero

v = dr/dt = (dx/dt)i+(dy/dt)j ... (3.15)

Hence x component of velocity is dx/dt

The x-coordinate, the x component of velocity, and the x component of acceleration are related by equations of straight line motion along X axis.
Similarly y components.


Projectile motion is an important example of motion in a plane.

What is a projectile? When a particle is thrown obliquely near the earth's surface, it is called a projectile. It moves along a curved path. If we assume the particle is close to the earth and negligible air resistance to the motion of the particle, the acceleration of the particle will be constant. We solve projectile problems with the assumption that acceleration is constant.

Vertical motion of the projectile is the motion along Y axis and horizontal motion is motion along X axis.

Terms used in describing projectile motion

Point of projection
Angle of projection
Horizontal range
Time of flight
Maximum height reached

The motion of projectile can be discussed separately for the horizontal and vertical parts.

The origin is taken as the point of projection.
The instant the particle is projected is taken as t = 0.
X-Y plane is the plane of motion.
The horizontal line OX is taken as the X axis.
Vertical line OY is the Y axis.
Vertically upward direction is taken as positive direction of Y

Initial velocity of the particle = u
Angle between the velocity and horizontal axis = θ

ux – x-component of velocity = u cos θ
ax – x component of acceleration = 0

uy – y component of velocity = u sin θ
ay = y component of acceleration = -g

Horizontal motion of the projectile – Equations of motion

ux = u cos θ
ax = 0
vx = ux +axt = ux = u cos θ (as ax = 0)
Hence x component of the velocity remains constant.
Displacement in horizontal direction = x = uxt+1/2ax t²
As ax = 0, x = ux t = ut cos θ

Vertical motion – Equations of motion
uy = u sin θ
ay = -g
vy = uy – gt
Displacement in y direction = y = uyt – ½ gt²
vy² = uy² - 2gy

22. Time of flight of the projectile = (2u sin θ)/g

23. OB = (u²sin 2θ)/g

24. t = (u sin θ)/g
At t vertical component of velocity is zero.

25. Maximum height reached by the projectile = (u² sin²θ)/2g

Wednesday, May 20, 2009

IIT JEE 2011 Physics Study Diary - Ch.3.Rest and Motion - Session 3

Day 3 Study Plan - To be studied on 23rd May 2009

3.6 Motion in a straight line
Ex., 3.7
WOE 3,4,5,6,

Points to Note

Motion in a straight line

As the motion is constrained to move on a straight line, choose the straight line in which motion is taking place as X-axis. Hence x represent the position of the particle at any time instant t. If you want you can imagine a graph between t and x but now t in on the vertical axis and x is on the horizontal axis.

Generally origin is taken at the point where the particle is situated at time t = 0.

Position of the particle at time t is given by x and also x measures displacement (not distance).
Velocity is v = dx/dt (3.9)
acceleration is a = dv/dt (3.10)
a = d²x/dt² (3.12)


If acceleration is negative, then it is along the negative X-axis. It is called deceleration

Motion with constant acceleration

Using integration the formulas for v velocity at any instant, x position at any instant and relation between v,u,x and a are derived in this section.

If acceleration is constant dv/dt = a (constant)
initial velocity = u (at time t =0)
final velocity = v (at time t)
Then v = u+at (3.12)

x = distance moved in time t = ut+½at² (3.13)

Also v² = u²+2ax (3.14)

u,v, and a as well as may take negative or positive values. When u, v and a are negative it shows velocity or acceleration is in the negative X direction.

Example 3.5
a) The question asked is distance travelled. The expression for x gives only displacement. But the remark is that as the particle does not turn back it is equal to distance travelled. Be careful when initial velocity is positive and the acceleration is negative.

Example 3.6
There was a past JEE question which is based on the variable defined in the example.

Freely falling bodies

In this case take the Y axis as the straight line on which the particle or body is moving.

You can take height above the ground as +y and work out the problems.

You can take the starting position of the body as the origin and work out the problem.
The choice may be yours or some choice may be more appropriate in case of some problems, be clear of the formula that you have to use depending on the choice you made.

g is approximately equal to 9.8 m/s², but for convenience in many problems it is given as 10m/s².

Tuesday, May 19, 2009

IIT JEE 2011 Physics Study Diary - Ch.3 Rest and Motion - Day 2

Plan for Day 2

4. Average velocity and instantaneous velocity
Ex. 3.4
Worked out example 2
3.5 Average accleration and instantaneous aceleration
WOE 3 to 4

Exercises: 1 to 5

Points to Note

Average velocity

Average speed and average velocity of a body over a specified time interval may not turnout to be same.

Example See the worked out example 2 of HC Verma's book.
The teacher made 10 rounds back and forth in the room and the total distance moved is 800 feet (10 rounds back and forth of 40 ft room). As the time taken is 50 minutes, average speed is 800/50 = 16ft/min.
But because he went out of the same door that he has entered, displacement is zero and hence average velocity is zero.

Instantaneous velocity

Average acceleration

Instantaneous acceleration

Position Vector: If we join the origin to the position of a particle by a straight line and put an arrow towards the position of the particle, we get the position vector of the particle.

If the particle moves from position A to position B, we can define position vector of A and position vector of B and OB - OA will give displacement ( a vector quantity).

Another point to note: slope of velocity-time diagram gives the instant acceleration at that point.

Monday, May 18, 2009

IIT JEE 2011 Physics Study Diary - Ch.3 Rest and Motion

I am planning to study the Physics chapters as per the study plan that I have given. Only thing I shall do to the extent possible in advance. This study would be of help to me in preparing JEE Level Revision problem set for each chapter.

Today (19.5.2009) I did the following portion

Day 1

3.1 Rest and Motion
3.2 Distance and displacement
Ex. 3.1
3.3 average speed and instantaneous speed
Ex. 3.2,3.3
Worked out examples 1,2

Points to note.

3.1 Rest and Motion

Motion is a combined property of the object under study and the observer. There is no meaning of rest or motion without the viewer.

To identify the rest or motion, we need to locate the position of a particle with respect to a frame of reference. The frame of reference will have three mutually perpendicular axes (X-Y-Z) and the particle can be represented by coordinates x,y,z.
If all coordinates remain unchanged as time passes, we say that particle is at rest. If there is change in any of the coordinates with time, we say the particle or the body represented by the particle is having motion.

I some problems or situations frame of reference is specifically mentioned. Otherwise the frame of reference is understood more easily from the context.

Figure 1: A man with a pistol threatening and asking people not to move.

3.2 Distance and Displacement

If a particle moves from position A to Position B in time t, displacement is the length of the straight line joining A to B. The direction of a vector representing this displacement is from A to B. Displacement is a vector quantity. It has both magnitude and direction.

In the movement between positions A and B the particle may take the path ACB. The length of the path ACB will be distance travelled by the particle. It is only scalar quantity. It has not direction.

3.3 Average speed and Instantaneous speed

The average speed of a particle in a specific time interval is defined as the distance travelled by the particle divided by the time interval.

We can plot the distance s as a function of time. In this graph, the instantaneous speed at time t equals the slope of the tangent at the time t. The average speed in a time interval t to t+Δt become equal to the slope of the chord Δs/Δt. As Δt becomes approaches zero, this average speed becomes instantaneous speed and ds/dt becomes the instantaneous speed.

If we plot a speed versus time graph ( v versus t), the distance travelled in time t (t1 to t2) will be equal to the area bounded by the curve v = f(t), x axis, and the two ordinates t = t1 and t = t2.

In terms of integration it can be represented as s = ∫vdt from t1 to t2

Sunday, May 17, 2009

IIT JEE Physics JEE Level Revision Questions

Hope you are revising the first chapter and doing the main study of second chapter.

I am slowly trying to develop a set of JEE level revision questions for each chapter of Physics.

I just initiated the exercise for chapter 1. See

I shall slowly add more problems. By January when you will be in serious revision mode all these chapters will have sufficient revision problems of JEE level.

Friday, May 8, 2009

IIT JEE 2011 Status of Study 9th May 2009


You are doing 1. Some basic concepts of chemistry.

Any doubts ask in the IIT JEE Academy Orkut Community. Ask your doubts early so that there is some time for the community members to reply. Don't get frustrated if the reply does not come immediately. You have to learn to go ahead if needed and come back when somebody gives you the reply.


You must have completed 1. Sets XI - May 1st to 7th
Ask doubt if any in the orkut community.

You are now doing 2. Cartesian product of sets and relations XI - May 8 to 14th (Revise ch. 1)


You are doing 1. Introduction to physics

From 11th May you have to start 2. Physics and mathematics. If required you can have a look at vectors chapter of mathematics as well as differentiation chapter. Any doubts ask in the orkut community.

Don't neglect studies. The amount to be studied gets piled up if you neglect now.

See the full May plan

Tuesday, May 5, 2009

JEE 2011 Study Plan

maths study plan - some more links were added for detailed plans of chapters

Monday, May 4, 2009

IIT JEE 2011 Chemistry Study Plan

Links are now provided to all chapters in the chemistry study plan for both the years.

Friday, May 1, 2009

IIT JEE 2011 -Ask doubts

As you are studying according to the plan, ask any doubts immediately. As many others may be studying the same chapter, clarifications may come from others very quickly.