Mechanics forms a major part of Physics as far as the JEE syllabus is concerned. Most of a candidate’s first year of preparation is devoted to mechanics in physics and rightly so. Mechanics for JEE Advanced has a significant weightage in the exam and the concepts involved are utilized almost everywhere in physics. Mechanics deals with the motion of objects in general so one can expect to find it’s use in almost everywhere.
Mechanics for JEE Advanced:
The JEE syllabus is limited to Newtonian Mechanics and doesn’t delve into Quantum Mechanics or Relativistic Mechanics. In a nutshell, Newtonian Mechanics deals with the study of macroscopic objects whose speed is much less than the speed of light. Most of the motion that we encounter in our day to day lives falls under the purview of Newtonian Mechanics and hence it is important to understand it thoroughly. In this branch of physics, nearly every subtopic is a mere application of the three fundamental laws of motion postulated by Newton. In general, there is very little to remember and a lot to understand and visualize in Mechanics. Unlike the study of Waves, which needs very little visualization and requires one to remember a lot of results, mechanics requires good visualization and imagination skills. Question solving typically involves following a series of steps in a methodological manner. One needs to have an absolutely clear understanding of every minute detail involved in solving the problem. The questions aren’t difficult but require a bit of thought to solve. If your concepts are clear, then mechanics will be your strength. So, if you understand this topic well, you shall be very comfortable with it. In this article, I have tried to put together some important things to remember while studying mechanics for JEE Advanced
Appropriately Draw a Diagram
This is the Golden Rule of mechanics that any teacher will tell you when it comes to solving problems. While solving any problem, one must draw what is called a ‘free body diagram’. The free body diagram should represent all the forces acting on every object of the system. Mechanics for JEE Advanced requires a lot of visualization and drawing a free body diagram will help you do just that. Make the diagram as illustrative as possible for your own convenience. Make sure that it is not too complicated or it may confuse you. A good diagram will help you visualize and can significantly decrease the time & effort required to solve the problem. It will make differences in places you can’t even imagine.
The Basic Laws
Mechanics doesn’t have a lot of theory. There are a few concepts and some laws using which every question can be solved. You need to understand these few things very well. You need to know each and every little detail about them. JEE Advanced is known for asking questions in which routine methods may prove be time taking. If you go through past question papers, you’d know. For such questions, you need to start right from scratch; apply the basic concepts and only then jump at the problem. Read the theory from a good book on physics. Multiple choice options of H.C. Verma – Concept of Physics help a lot in concept building. You could also refer the internet during preparation. Discussions on forums do give you a lot of knowledge.
In Mechanics, concept is a necessary condition but not a sufficient one. The application of this concept in solving problems involves many assumptions to make the problem solvable. It is one thing to know what is Newton’s Law and another thing to know how to use it in solving problems. You can read up a lot of literature on theory but you will really understand it only when you have solved problems. Hence, it is best to practice a lot especially when it comes to Mechanics for JEE Advanced.
Also while solving a particular problem one must do some lateral thinking. When you are asked to find out a particular quantity associated with a system try to understand how various components of the system affect the value of the quantity. For example, if you are to find the acceleration of a block connected to a pulley placed on an inclined plane, try to find how it varies with the inclination of the plane, the mass of the block and the coefficient of friction of the block and the plane. This will present deeper insights into the problem. Questions are often asked in JEE which involve qualitative analysis of the system. Mostly, they appear in ‘more than one option correct’ type questions or in matrix match. Your analytical ability will help you here. Know very well what assumptions are made by you and be careful while using them in problems.
An Overview of Past Papers
Mechanics for JEE Advanced generally has a high weightage owing to the vastness of the syllabus. Compared to electrodynamics, you have to put in more effort here for a lower weightage. However, concepts of mechanics are used in almost every part of physics so indirectly it has a very high weightage. The table below shows the number of questions asked in the last few years. However, I would warn you that it is criminal to classify any JEE question as based on a single topic. Most of the questions involve a mixture of concepts from multiple chapters and no single chapter as such.
|Chapter||Weightage in 2013(No. of questions)||Weightage in 2014(No. of questions)||Weightage in 2015(No. of questions)|
|Centre of Mass||–||1||–|
|Rigid Body Dynamics||–||2||3|
|Simple Harmonic Motion||2||–||1|
|Fluid Mechanics and Properties of Matter||2||5||2|
|Laws of Motion and Friction||2||2||2|
|Work, Energy and Power||2||1||2|
As can be seen, the often neglected chapters viz. fluid mechanics and mechanical properties of matter have a significant weightage. So do not ignore them.
To sum things up, Mechanics for JEE Advanced is an important part of physics which is used almost everywhere and hence one ought to be good at it. It is necessary to know the basic concepts very well and know how to use them by practicing problems. I would like to add that one needs to be good at solving systems of linear equations to do the calculations part quickly. But that is certainly not the most problematic part of Mechanics. The most important is good theoretical knowledge and visualization skills. Do this well and Mechanics will be your strength.
JEE advanced is a beast and conquering it is hard work. I hope this article was helpful to you. Good Luck! 🙂