Next question, question 2018, Neet ki exam mein puchagayain, this is one of my favorite question. It says, the body initially at rest and sliding along a frictional strike from the height h as shown in the diagram, just completes a vertical circle of diameter AB is equal to D, we have to tell you how high it is. Now, this is an interesting question, because it has two chapters of concepts, workpainergy and vertical circle emotion. Situation is expected to be that this is our incline plane, let's say angle theta, this is a particle from here, move the start and tell you this height will be attached. And that particle, when it reaches this location, which is the bottommost point, here, it has completed a vertical circle and vertical circle has given its diameter, let's say it is radius R, so diameter we can always say will be equal to 2R or R will be equal to D by 2. Now, to complete the vertical circle, just to complete, this location should have its own velocity, V minimum value is under root of 5GR. So, it will be under root of 5G by 2, this is the minimum velocity, here, then the particle will be completed by its vertical circle. Now, if we look here, work done by external 4 is 0, work done by pseudo 4 is 0, work done by non-conservative force is 0, because frictionless surface is 0. In this case, we easily start our work energy, we can consider energy. So, what that means is, what is the potential energy initial plus kinetic energy initial will be equal to potential energy final plus kinetic energy final. Now, if you want to zero the potential energy on this location, then we can write the potential energy initial value of mGH. So, potential energy initial mGH, kinetic 0, because the rest is gone. When this location reaches here, we have to zero the potential energy, zero is equal to zero. Plus, here energy will be kinetic energy, that energy will be half mV square. So, based on this mass will get cancelled, mM mass on both sides will get cancelled. It will cancel, hq value will be v square divided by 2G. Now, if we value V, we will put under root of 5G by 2V, so it will be under root of 5G divided by 2G, G again will cancel, so it will be cancelled. 5D by 4. So, your final value is option number D, it has got correct answer.