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Why Cats Land on Their Feet

Book Description

Ever wonder why cats land on their feet? Or what holds a spinning top upright? Or whether it is possible to feel the Earth's rotation in an airplane? Why Cats Land on Their Feet is a compendium of paradoxes and puzzles that readers can solve using their own physical intuition. And the surprising answers to virtually all of these astonishing paradoxes can be arrived at with no formal knowledge of physics.

Mark Levi introduces each physical problem, sometimes gives a hint or two, and then fully explains the solution. Here readers can test their critical-thinking skills against a whole assortment of puzzles and paradoxes involving floating and diving, sailing and gliding, gymnastics, bike riding, outer space, throwing a ball from a moving car, centrifugal force, gyroscopic motion, and, of course, falling cats.

Want to figure out how to open a wine bottle with a book? Or how to compute the square root of a number using a tennis shoe and a watch? Why Cats Land on Their Feet shows you how, and all that's required is a familiarity with basic high-school mathematics. This lively collection also features an appendix that explains all physical concepts used in the book, from Newton's laws to the fundamental theorem of calculus.

Table of Contents

  1. Cover
  2. Title
  3. Copyright
  4. Contents
  5. Acknowledgments
  6. 1 Fun with Physical Paradoxes, Puzzles, and Problems
    1. 1.1 Introduction
    2. 1.2 Background
    3. 1.3 Sources
  7. 2 Outer Space Paradoxes
    1. 2.1 A Helium Balloon in a Space Shuttle
    2. 2.2 Space Navigation without Jets
    3. 2.3 A Paradox with a Comet
    4. 2.4 Speeding Up Causes a Slowdown
  8. 3 Paradoxes with Spinning Water
    1. 3.1 A Puzzle with a Floating Cork
    2. 3.2 Parabolic Mirrors and Two Kitchen Puzzles
    3. 3.3 A Cold Parabolic Dish
    4. 3.4 Boating on a Slope
    5. 3.5 Navigating with No Engine or Sails
    6. 3.6 The Icebergs
  9. 4 Floating and Diving Paradoxes
    1. 4.1 A Bathtub on Wheels
    2. 4.2 The Tub Problem—In More Depth
    3. 4.3 How to Lose Weight in a Fraction of a Second
    4. 4.4 An Underwater Balloon
    5. 4.5 A Scuba Puzzle
    6. 4.6 A Weight Puzzle
  10. 5 Flows and Jets
    1. 5.1 Bernoulli’s Law and Water Guns
    2. 5.2 Sucking on a Straw and the Irreversibility of Time
    3. 5.3 Bernoulli’s Law and Moving Around in a Space Shuttle
    4. 5.4 A Sprinker Puzzle
    5. 5.5 Ejecting Water Fast but with Zero Speed?
    6. 5.6 A Pouring Water Puzzle
    7. 5.7 A Stirring Paradox
    8. 5.8 An Inkjet Printer Question
    9. 5.9 A Vorticity Paradox
  11. 6 Moving Experiences: Bikes, Gymnastics, Rockets
    1. 6.1 How Do Swings Work?
    2. 6.2 The Rising Energy Cost
    3. 6.3 A Gymnast Doing Giants and a Hamster in a Wheel
    4. 6.4 Controlling a Car on Ice
    5. 6.5 How Does a Biker Turn?
    6. 6.6 Speeding Up by Leaning
    7. 6.7 Can One Gain Speed on a Bike by Body Motion Only?
    8. 6.8 Gaining Weight on a Motorbike
    9. 6.9 Feeling the Square in mv 2/2 Through the Bike Pedals
    10. 6.10 A Paradox with Rockets
    11. 6.11 A Coffee Rocket
    12. 6.12 Throwing a Ball from a Moving Car
  12. 7 Paradoxes with the Coriolis Force
    1. 7.1 What Is the Coriolis Force?
    2. 7.2 Feeling Coriolis in a Boeing 747
    3. 7.3 Down the Drain with Coriolis
    4. 7.4 High Pressure and Good Weather
    5. 7.5 What Causes Trade Winds?
  13. 8 Centrifugal Paradoxes
    1. 8.1 What’s Cheaper: Flying West or East?
    2. 8.2 A Coriolis Paradox
    3. 8.3 An Amazing Inverted Pendulum: What Holds It Up?
    4. 8.4 Antigravity Molasses
    5. 8.5 The “Proof” That the Sling Cannot Work
    6. 8.6 A David–Goliath Problem
    7. 8.7 Water in a Pipe
    8. 8.8 Which Tension Is Greater?
    9. 8.9 Slithering Ropes in Weightlessness
  14. 9 Gyroscopic Paradoxes
    1. 9.1 How Does the Spinning Top Defy Gravity?
    2. 9.2 Gyroscopes in Bikes
    3. 9.3 A Rolling Coin
    4. 9.4 Staying on a Slippery Dome
    5. 9.5 Finding North with a Gyroscope
  15. 10 Some Hot Stuff and Cool Things
    1. 10.1 Can Heat Pass from a Colder to a Hotter Object?
    2. 10.2 A Bike Pump and Molecular Ping-Pong
    3. 10.3 A Bike Pump as a Heat Pump
    4. 10.4 Heating a Room in Winter
    5. 10.5 Freezing Things with a Bike Tire
  16. 11 Two Perpetual Motion Machines
    1. 11.1 Perpetual Motion by Capillarity
    2. 11.2 An Elliptical Mirror Perpetuum Mobile
  17. 12 Sailing and Gliding
    1. 12.1 Shooting Cherry Pits and Sailing
    2. 12.2 Sailing Straight into the Wind
    3. 12.3 Biking against the Wind
    4. 12.4 Soaring without Updrafts
    5. 12.5 Danger of the Horizontal Shear Wind
  18. 13 The Flipping Cat and the Spinning Earth
    1. 13.1 How Do Cats Flip to Land on Their Feet?
    2. 13.2 Can Trade Winds Slow Earth’s Rotation?
  19. 14 Miscellaneous
    1. 14.1 How to Open a Wine Bottle with a Book
    2. 14.2 “It’s Alive!”
    3. 14.3 Falling Faster Than g: A Falling Chain “Sucked in” by the Floor
    4. 14.4 A Man in a Boat with Drag
    5. 14.5 A “Phantom” Boat: No Wake and No Drag
    6. 14.6 A Constant-G Roller Coaster
    7. 14.7 Shooting at a Cart
    8. 14.8 Computing 2 with a Shoe
  20. Appendix
    1. A.1 Newton’s Laws
    2. A.2 Kinetic Energy, Potential Energy, Work
      1. A.2.1 Work
      2. A.2.2 Kinetic Energy
      3. A.2.3 Potential Energy
      4. A.2.4 Conservation of Energy
    3. A.3 Center of Mass
    4. A.4 Linear Momentum
    5. A.5 The Torque
    6. A.6 Angular Momentum
    7. A.7 Angular Velocity, Centripetal Acceleration
    8. A.8 Centrifugal and Centripetal Forces
    9. A.9 Coriolis, Centrifugal, and Complex Exponentials
    10. A.10 The Fundamental Theorem of Calculus
  21. Bibliography
  22. Index