Watch part 2 (https://www.youtube.com/watch?v=leO3sLpq3oc) for completely understanding conservation of mechanical energy. In this lecture, a short trick to identify the problems which can be solved using conservation of mechanical energy has been discussed.As you may all know this conservation principle will be used in most of the chapters in class 11 and 12, so its importance cannot be overstated.So IIT/NEET/board students may all find it very useful. The total work done by a mass-less in-extensible string is always zero. The same is true for normal force(valid for collisions also if there is no deformation in the colliding objects-will be discussed in detail in the next chapter), so the only non-conservative internal force or the external force(depending on the system chosen) whose work needs to be zero for conservation of mechanical energy of a system is friction. Please note that in all the cases involving gravitational potential energy we must take Earth also as part of the system.But since this lecture was intended to solve these questions quickly I did not mention taking Earth as part of the system.The answer will come out to be the same but remember the gravitational potential energy belongs to Earth-block system and not to only the block or the Earth. Lastly try to solve as many problems as possible on this topic to gain confidence in this short-trick.Comment if you cannot solve a problem via this method. Work energy power https://www.youtube.com/watch?v=xqPdwx9NFg4&list=PLk5kuyX3xzda9o8omsAO60taH95l-ox2S Constrained motion https://www.youtube.com/watch?v=50NKNJ8Q8CU&list=PLk5kuyX3xzdaXBPcpuNlzY6uxav0mscrZ Circular motion https://www.youtube.com/watch?v=jDLUqMgp_VA&list=PLk5kuyX3xzdZTAEnlfvaTo01snIe8ai3y Magnetic field due to current https://www.youtube.com/watch?v=fF5RtOVY0_o&list=PLk5kuyX3xzdbFqDlzAXboU9pqtDMxbej- Electromagnetic induction EMI https://www.youtube.com/watch?v=Hgsfkezyvys&list=PLk5kuyX3xzdZq-3AoQFc7Mh_0OBBJ67sA ... https://www.youtube.com/watch?v=sLgLFVcQSLA

Complete theory lectures on 'Center of mass, Linear Momentum and Collision' followed by PYQs, HCV solutions and other important problems: https://www.youtube.com/playlist?list=PLk5kuyX3xzdZ_xC1xR7Ay2oeQp74w-T6A ... https://www.youtube.com/watch?v=Pav1SOhhMc4

50 Solved problems on vectors-Part 1. This video is intended for JEE NEET Class 11 students. For detailed theory please watch this playlist :https://www.youtube.com/watch?v=w9TnoDvnTrg&list=PLk5kuyX3xzdaARS3BRipgU2G_yocoYZ4m ... https://www.youtube.com/watch?v=flbDsC_i8zI

Part 1: https://youtu.be/H9Tp6W5WWJM ... https://www.youtube.com/watch?v=0tBzSWKRUoE