Physics System of Particles and Rotational Motion

Well, the centre of mass is a single point. It does not rotate by itself. But an object or a system of particles can rotate about its centre of mass. The individual particles of a system can move around the centre of mass, and these particles can make the centre of mass move in a straight line at a constant velocity unless there is a net external force. This is pretty much Newton's First Law, because we are talking about motion in general.  

Centre of mass becomes easier to calculate when you are confident with concepts such as weighted average and mass distribution. But this concept can be challenging when applying to complex systems and in combination with rotational motion. Either way, you will need to build a solid foundation with kinematics, Newton's Laws, and work-energy principles before approaching the centre of mass concept in the Systems of Particles and Rotational Motion chapter in Physics Class 11.   

Yes, it's an important concept to tackle JEE Main questions on rotational mechanics, rigid bodies, and collisions. Learning about the centre of mass simplifies complex motions of objects by treating the entire mass into a single point.  In exams such as JEE, questions on centre of mass are also interrelated with other advanced concepts in physics. So, a thorough conceptual understanding of it is essential.   

$I_{OO\text{'}}=\left[\frac{1}{4}M{\left(\frac{a}{2}\right)}^2\right]*2+\left[\frac{5}{4}m{\left(\frac{a}{2}\right)}^2\right]*2$

$=\frac{6M{a}^2}{8}=\frac{3}{4}M{a}^2$

x=3

An excellent example of pure rotational motion is the motion of the blades of a ceiling fan when it is switched on. In this type of motion, the object rotates about a fixed axis, and all particles of the object move in circles centred on that axis. Windmills and turbines also follow the same rotational mechanics. 

Rotational motion in Class 11 Physics is regarded as a challenging chapter, particularly due to the transition from point particles to extended bodies. Additionally, the concepts covered here are analogous to, yet distinct from, linear motion. Even vector calculations here can be difficult. But the key to mastering this chapter is to be conceptually clear with your previous chapters in Physics. You also need to be able to visualise rotational motion instead of memorising definitions, to be able to master it.  

Yes, rotational motion is important for the NEET exam. Expect and prepare for, at least, two to three questions on rotational motion as per the latest NEET Physics syllabus for Mechanics. Questions from this chapter are clubbed into the application of principles from other areas of mechanics, such as Laws of Motion, Work, Energy, and Power, and Conservation of Momentum. 

$\theta ={\omega }_{0}t+\frac{1}{2}\alpha t^2$

$5=0*1+\frac{1}{2}*\alpha *1^2$

= 10 rad/sec²

(ln 2 seconds) = ${\omega }_{0}t+\frac{1}{2}\alpha t^2$

${\theta }_2=20rad$

Angle rotated by wheel in 2^nd second

= ${\theta }_2-\theta$

= 20 – 5

= 15 rad