Block over Block Friction (Part-2) for JEE(Adv) | Class 11 Physics in Minutes| #PhysicsGalaxyPIM

In JEE Advanced topic of friction between block over block problems is very important and it forms the basic understanding in dynamics. Ashish Arora sir has explained all the concepts related to application of friction when a block over another block is placed and lower block is pulled by an external force. The concepts Analyzed in this video are given below. Concept-1 : Block over block on smooth surface with external force on lower block Concept-2 : Understanding and condition of common Motion of block with force on lower block Concept-3 : Block over block on smooth surface with external force on upper block Concept-4 : Limiting condition of common motion of blocks with force on upper block Concept-5 : Block over block on rough surface with force on upper block Concept-6 : Case analysis when upper limiting friction is smaller than lower limiting friction Concept-7 : Case analysis when upper limiting friction is larger than lower limiting friction Concept-8 : Understanding of case when lower block never slides Concept-9 : Understanding of case when upper block never slides (when middle surface is smooth) Concept-10 : Sliding condition in every case - friction at surface becomes equal to limiting friction Detailed understanding of the concept can be covered through the Physics Galaxy Concept videos available through our channel playlist or our website. https://www.physicsgalaxy.com Students can follow our channel updates on our facebook page.   / physicsgalaxy74   To understand all the applications of friction and dynamics, students can refer our Physics Galaxy series of books. These books are available for purchase at below link - http://edyapp.com/physics-galaxy-books Based on above video some questions are given below in comment section which students can solve and check if they are able to solve these questions using the concept explained in above video. Out of 5 questions given below for third question answers are not given. Students are advised to post the answer of this question in comments to discuss and verify if their answer is correct. Practice Questions for students on concept of above video. Students are required to solve these questions and verify the answers given. Out of below given Solve the question, in ONE question given answer is wrong. Solve and post that question no of which answer is wrong and post the correct answer in comment section for discussion and verifying your result. In all below questions take g = 10m/s². Practice Quiz Questions - Q1. A 4kg block is placed over 5kg block on a smooth ground. Friction coefficient between 5kg and 4kg is 0.5. A force F is applied horizontallay on 5kg block. Find at what value of F sliding will start between the two blocks ? Ans [45N] Q2. A 4kg block is placed over 5kg block on a smooth ground. Friction coefficient between 5kg and 4kg is 0.5. A force F is applied horizontallay on 4kg block. Find at what value of F sliding will start between the two blocks ? Ans [36N] Q3. A 5kg block is placed over 10kg block on a smooth ground. Friction coefficient between 5kg and 10kg blocks is 0.2. A force F is applied horizontallay on 5kg block. Find at what value of F sliding will start between the two blocks ? Ans [15N] Q4. A 10kg block is placed over 20kg block on a rough ground. Friction coefficient between 20kg and ground is 0.2 and that between the two blocks is 0.1. A force F is applied horizontalay on 10kg block. Find at what value of F sliding will start between 20kg and ground then at which value sliding will start between the two blocks ? Ans [On ground never start, between the blocks at 10N] Q5. A 20kg block is placed over 20kg block on a rough ground. Friction coefficient between lower 20kg and ground is 0.1 and that between the two blocks is 0.6. A force F is applied horizontallay on upper 20kg block. Find at what value of F sliding will start between lower block and ground then at which value sliding will start between the two blocks ? Ans [40N, 280N] #physicsinminutes #physicsgalaxy #ashisharora #physicsgalaxypim