OpenStax University Physics Vol 1 | Ch10 Sec7 | Newton's Second Law for Rotation and Problem Solving

OpenStax University Physics Vol 1 | Ch10 Sec7 | Newton's Second Law for Rotation With AP Physics C: Mechanics Problem Solving Use net torque and moment of inertia to determine angular acceleration, then connect rotational dynamics to the motion that follows. This OpenStax University Physics Volume 1 lesson derives the fixed-axis form of Newton's second law, net torque = I alpha. Choose a consistent axis and sign convention, draw the forces, and distinguish driving torque from frictional resistance. Solve braking and spin-up problems for grinding wheels, disks, and flywheels, including stopping angles, turn counts, and torque removal. Analyze a block sliding down an incline while unwinding a tether from a massive pulley. Use separate force and torque equations with the no-slip condition to recover acceleration and tension, and check the result against energy and the massless-pulley limit. WHAT YOU'LL LEARN Derive the fixed-axis torque law; match inertia and torque to the same axis; calculate frictional torque; combine dynamics with constant-acceleration kinematics; stop a braking model at rest; distinguish pulley tensions; use a = r alpha; solve coupled translation and rotation. RESOURCES & LINKS InspiredK.org — free education and more courses: https://www.inspiredk.org Course roadmap: https://www.inspiredk.org/university-... OpenStax University Physics Volume 1, Section 10.7 — access for free: https://openstax.org/books/university... Full course playlist:    • OpenStax University Physics Vol 1 | Full C...   Course introduction:    • OpenStax University Physics Vol 1 | Ch1, S...   AP Physics C: Mechanics course framework: https://apcentral.collegeboard.org/co... AP PHYSICS C CONNECTION AP Physics C: Mechanics, Unit 5, Topic 5.6: Newton's Second Law in Rotational Form, with connections to rotational kinematics and no-slip motion. VIDEO CHAPTERS 00:00 Introduction: Newton's second law for rotation 00:38 OpenStax and AP Physics C connection 01:30 Tangential force and angular acceleration 01:56 Multiplying the force equation by radius 02:20 Adding particles in a rigid body 02:45 The fixed-axis law: Net torque equals I alpha 03:11 Use the same axis for torque and inertia 03:35 Choosing signs for rotational dynamics 04:00 Comparing acceleration at different inertias 04:26 Rotational free-body diagrams 05:07 Frictional torque at a rim 05:36 Driving and resisting torques 05:59 Constant torque with constant inertia 06:24 From dynamics to kinematics 06:48 Ending a braking model at rest 07:12 Why a massive pulley needs unequal tensions 07:35 No-slip translation and rotation 08:04 Separate equations for separate bodies 08:29 Effective pulley inertia in a linear equation 09:00 Checking the massless-pulley limit 09:23 Freely accelerating versus supported rotors 09:50 A solution and verification sequence 10:17 Problem 84: Braking a rotating disk 10:50 Problem 84: Friction force and disk inertia 11:11 Problem 84: Angular deceleration 11:34 Problem 84: Stopping angle and revolutions 11:54 Problem 84: Work-energy check 12:15 Problem 85: Driving torque with axle friction 12:48 Problem 85: Torque and moment of inertia 13:11 Problem 85: Acceleration without friction 13:30 Problem 85: Resistance at a smaller radius 14:13 Problem 86: Flywheel spin-up 14:40 Problem 86: Constant rate-change model 15:02 Problem 86: Acceleration and motor torque 15:41 Problem 86: Motion and energy check 16:01 Problem 87: Torque from a measured rate change 16:48 Problem 87: Acceleration and required torque 17:32 Problem 87: Scaling check 17:51 Problem 88: Grinding wheel under constant torque 18:18 Problem 88: Angular acceleration 18:39 Problem 88: Rate when torque is removed 18:58 Problem 88: Angular displacement and energy check 19:34 Problem 93: Block, incline, and massive pulley 20:05 Problem 93: Force equation for the block 20:28 Problem 93: Pulley torque and no slip 20:53 Problem 93: Solving for acceleration 21:20 Problem 93: Recovering tension and checking 21:45 Torque-time interpretation 22:09 Energy check for coupled motion 22:31 Scope of the fixed-axis law 22:55 Reasoning check 23:28 Section summary PRACTICE ALONG Problems 84, 85, 86, 87, 88, and 93, including the frictional incline and massive-pulley system. Exercise numbers refer to OpenStax University Physics Volume 1, Chapter 10. Pause at each question, try it yourself, then compare your reasoning with the solution. Want More College Courses? 🔔 Subscribe & Turn on Notifications! 👍 Like the video to support free education! 💬 Have questions or thoughts? Drop a comment below! Let’s discuss and learn together! LET'S DISCUSS Why can the tensions on the two sides of a massive accelerating pulley differ even when the connecting string is ideal? #RotationalDynamics #Torque #APPhysicsC #InspiredK.org