Ch 13: Torque & Rotational DynamicsWorksheetSee all chapters
All Chapters
Ch 01: Intro to Physics; Units
Ch 02: 1D Motion / Kinematics
Ch 03: Vectors
Ch 04: 2D Motion (Projectile Motion)
Ch 05: Intro to Forces (Dynamics)
Ch 06: Friction, Inclines, Systems
Ch 07: Centripetal Forces & Gravitation
Ch 08: Work & Energy
Ch 09: Conservation of Energy
Ch 10: Momentum & Impulse
Ch 11: Rotational Kinematics
Ch 12: Rotational Inertia & Energy
Ch 13: Torque & Rotational Dynamics
Ch 14: Rotational Equilibrium
Ch 15: Angular Momentum
Ch 16: Periodic Motion
Ch 17: Waves & Sound
Ch 18: Fluid Mechanics
Ch 19: Heat and Temperature
Ch 20: Kinetic Theory of Ideal Gasses
Ch 21: The First Law of Thermodynamics
Ch 22: The Second Law of Thermodynamics
Ch 23: Electric Force & Field; Gauss' Law
Ch 24: Electric Potential
Ch 25: Capacitors & Dielectrics
Ch 26: Resistors & DC Circuits
Ch 27: Magnetic Fields and Forces
Ch 28: Sources of Magnetic Field
Ch 29: Induction and Inductance
Ch 30: Alternating Current
Ch 31: Electromagnetic Waves
Ch 32: Geometric Optics
Ch 33: Wave Optics
Ch 35: Special Relativity
Ch 36: Particle-Wave Duality
Ch 37: Atomic Structure
Ch 38: Nuclear Physics
Ch 39: Quantum Mechanics

Concept #1: Torque Due to Weight

Practice: Two kids play on a seesaw that has mass 20 kg, length 3 m, and its fulcrum at its mid-point. The seesaw is originally horizontal, when the kids sit at the edge of opposite ends (m,LEFT = 25 kg, m,RIGHT = 30 kg). Calculate the Net Torque from the 3 weights acting on the seesaw, immediately after the kids sit (simultaneously) on their respective places.

Practice: A guy standing straight up stretches out his arm horizontally while holding a 60 lb (27.2 kg) barbell. His arm is 64 cm long and weighs 45 N. Calculate the Net Torque that the barbell and the weight of his arm produce about his shoulder. You may assume that his arm has uniform mass distribution.