Learning Topper Education For Competative Exams

7 July 2012

Newton's Law of Motion -

5.2 Newton's second law 5.3 Working with Newton's laws W.O.E. 3 and 4 5.2 Newton's second law The acceleration of a particle as measured from an inertial frame is given by the (vector) sum of all the forces acting on the particle divided by its mass. a = F/m or F = ma Acceleration and force are measured at the same instant. If force becomes zero at an instant, acceleration also becomes zero at the same instant. 5.3 Working with Newton’s First and Second Law 1. Decide the System We have to assume that forces are acting on a system and the system is at rest or in motion. In this context, the system may be a single particle, a block, a combination of two blocks one kept over the other or two blocks connected by a string etc. But there is a restriction for treating one as a system. All parts of the system should have identical acceleration. Step 2. Identify the Forces Once the system is decided, make a list of the forces acting on the system due to all the objects other than the system. Any force applied by the system should not be included in the list of the forces (material from the chapter on forces should help you in deciding various forces exerted by the system and forces exerted by the objects on the system). Step 3. Make a Free Body Diagram Represent the system by a point in a separate diagram and draw vectors representing the forces with this point as the common origin Step 4: Choose axes and Write Equations. Example 5.2 The example describes a block being pulled by a man with help of a string. The system under analysis is the block. It is accelerating in the horizontal direction. So there is net force in the horizontal direction. It is not accelerating in the vertical direction. Hence net force is vertical direction is zero. Worked out examples: 3,4,5, Obective I 3,5, 6,9,10, Attempt questions in Objective questions (OBJ II) 4 Exercises

6 July 2012

Higgs Boson

‎:::::::::::::Higgs Boson:::::::::::

You might have heard about the Large Hadron Collider. The search for the God particle is a key task for the Large Hadron
Collider, which straddles the borders of France and Switzerland. It was designed to reveal the secrets of the universe by recreating the conditions that
existed immediately after the big bang.
Here are the top 10 facts about the incredible machine.

1. It cost £2.6 billion to build L.H.C.

2. It houses 9300 magnets – pre- cooled to -193.2C, using 10,080 tonnes of liquid nitrogen. They
are then taken down to -271.3C with liquid helium.

3. It fires protons and lead ions around a 17 mile circulartunnel.

4. The protons, when the machine is cranked up to full power, travel at a mind-blowing 99.9999991% of the speed of light – or 11,245 laps every second – or671,000,000 mph.

5. 600m collisions take place every second.

6. The collisions generate temperatures more than 100,000 times hotter than the heart of the Sun.

7. The inside of the accelerator is an ultra-high vacuum – a cavity as empty as interplanetary space. This is so the protons avoid collisions with gas molecules.

8. A total of 10,000 scientists and engineers from more than 60 countries work on LHC.

9. The most powerful supercomputer system in the world was built to analyse the data generated by the LHC. It’s called the Grid and is formed
from tens of thousands of interconnected computers scattered around the world. The
data recorded by each of the big experiments at the LHC will fill around 100,000 dual-layer DVDs every year.

10. There’s even an LHC rap, which pretty much explains everything.

IIT JEE Chemistry Concepts Revision Materials

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Revision points for revision at the end of study of a chapter as well as for periodic and final revisions. These revision points will be scheduled as a plan for revision for JEE 2010 and JEE 2011 during (January 2010 to April 2010)