 Hello everyone, I am Mr. Sachin Rathod, working as an assistant professor in mechanical engineering department from Washington School of Technology College. Today we are seeing the further parts of the break, the learning outcome of the session is we will able to understand the working of single block or shoe break. So in the last lecture, we have seen the case 2 that is when the block, the drawing is rotated in the anticlockwise direction, we are applying the force P in the non-wire direction. So we are getting the value of the P that is the Rn in bracket A-mu be divided by the Pl. So from this equation, we will get the concept of, from this equation, we will get the concept of self-analytic or self-locking break. So you can think about this, what is mean by self-locking break and the self-analytic break. Let us see, the self-locking break is nothing but without applying any kind of the external force, the rotating draw will get stopped. So that is called as a self-locking break and the self-analytic break is nothing but, so some amount of the frictional force will minimize the effort, that is the force that is called as a self-analytic break. So we will see the both concepts. So here in that equation, that is the P equation, that is the force applied, we are observing that here is A-mu be, if A is less than or equal to mu be, then we are getting the value of the P is 0 or negative. It means that without applying any kind of the force on the lever, the drum will get stopped. So such condition is called as a self-locking break. So this is a condition for, this is a condition for the self-locking break. That is that A should be less than or equal to the mu be. So the next one, that is the P is equal to A, if you multiply this A into the Rn-mu Rn into the B divided by the L. So here the this concept, this bit A into the Rn is nothing but movement of normal reaction about the fulcrum and mu Rn into the B is movement of frictional force, force that is the f is equal to mu Rn movement of frictional force about fulcrum. So in that equation, we are observing that this movement of frictional force that is the mu Rn about the fulcrum shows the negative value means it minimizes the effort applied at the end of the lever that it minimizes the P. So this condition will reduces the effort at the end of the lever. So such condition is called as self-locking. Energize the break means it reduces the effort. So in our actual case the break should be the self-energize the and it should not be the self-locking break. So we have seen the two bit, first one self-locking break and second self-energize the break. So now we will see the third case that is when the line of the action of the breaking force passes through the distance B above the fulcrum point O of the lever and the break will rotate in the clockwise direction. So this condition that this is the drum, log, this is the lever and that is the O point below this B distance, length of the lever, the force is applied at the distance A and B distance, suppose this is the B distance as the drum rotates in the clockwise direction, the friction force f is equal to mu Rn and this is the normal reaction Rn. Now we have to calculate the breaking torque. So same here is there as dB is equal to f friction force f into the radius of the drum, f is equal to mu Rn into the radius of the drum and for calculating the value of the Rn you have to take the moments about this fulcrum. So therefore P into L minus Rn into mu A, as we will get in the clockwise direction, so plus mu Rn into stress B is equal to 0. Therefore P L is equal to Rn into A minus mu Rn into P. Therefore P L is equal to Rn bracket A minus mu B therefore Rn is equal to P L upon A minus mu B therefore TB is equal to mu into P L upon A minus mu B into R. So here also we are observing that A minus mu B term is there, so here also the two cases are there that is the self locking and self analyzing the break. So as the break is rotated in the clockwise direction now we will see the next drum rotates in the anticlockwise direction. This is the drum rotates in the anticlockwise direction, this is the P force, this is the position of fulcrum O, that is the B distance 0, this is the A, this is the length of the bridge. So as the drum rotates in the anticlockwise direction, force F will be acting like this. So you have to take the moments about O therefore we are getting P into L minus Rn into the distance A and this minus F into B is equal to 0. Therefore P into L is equal to Rn into A plus F into B is equal to Rn into A plus F is equal to mu Rn into B is equal to Rn in bracket A plus mu B therefore Rn is equal to P L upon A plus mu B into R. So by using this equation we can easily calculate the breaking torque under this condition. So depending upon these conditions the numerical are there, so we will see that in the next session. These are my references. Thank you.