Newton's First Law of Motion: Inertia 
Newton's First Law of Motion: Inertia
by Prof. Miller
Video Lecture 2 of 46
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Date Added: February 5, 2015

Lecture Description

The MASS of a body is a measure of its inertia. The WEIGHT of a body is the FORCE with which the Earth pulls on it. MASS is - as we say -invariant - it is the same everywhere; WEIGHT varies from place to place. NEWTON'S FIRST LAW has to do with INERTIA. It says this: A body at rest wishes to remain at rest; a body in uniform motion in a straight line wishes to do this. Allthe demonstrations in this program near on these great ideas.

A - We show a block of mass M. IT wants to remain at rest "so much" . A block of mass 2M wants to remain at rest TWICE AS MUCH. So too on April Fool's Day does a package of bricks behave!

B - The HEAVY block with the dowel-rod handle stays at rest if it is at rest; it keeps on going if THAT is what it is doing.

C - We show a sequence of simple, utterly-simple, plebeian DEMONSTRA¬TIONS bearing out the strength and beauty of this "apparently" trivial FIRST LAW. But we must remember that it took the genius of a Newton to first formulate it!
1 - A mass with two strings. We break the lower one OR the upper
one utilizing Newton.
2 - A HEAVY sphere is pulled upward on a string - first gently -
slowly — then suddenly - impulsively.
3 - A brick in the hand can be struck a severe blow and the hand
feels "NOTHING"!
4 - The mass of air on a sheet of paper has ENORMOUS INERTIA.
5 - A glass of water can be dragged along* gently on a piece of
paper but a sudden pull on the paper leaves the glass at rest. NOTE: The glass of water stays on the very edge of the table if its CENTER OF GRAVITY is NOT beyond the edge. See Program #1 on CENTER OF GRAVITY.
6 - A vehicle is at rest. It starts suddenly forward. Your head is
jerked backwards. NO! This is not right. Your head was at rest and it wishes to stay at rest! Now the vehicle is moving for¬ward. Suddenly it is brought to rest. YOU fly forward! Very dangerous!
7 - A pint of milk has greater inertia than a pint of cream. Milk Is
heavier than cream!
8 - A stack of coins stands erect - one atop another. The very bottom
one can be driven out with a sharp flat blade without troubling the others. This is a wonderful thing to do - you can even play it like a game. The STACK has great INERTIA and wishes to remain at rest.

D - A ball is whirled in a vertical circle on the end of a string. At the top of the path the ball is at this instant moving tangentially to the path -that is - in a straight line. If now we cut the string or let go of it what does the ball do? ANSWER: The ball goes off in the direction it was going - tangent to the circle. It does NOT fly out radially! Here we see the SECOND part of Newton's First Law beautifully demonstrated.

E - We show a likeness of Newton. The work of men must always be con¬nected with the men. In this way we acquire a warmer and deeper feeling for those who made these wonderful contributions to our Know¬ledge and Understanding.

Course Index

  1. The Idea of the Center of Gravity
  2. Newton's First Law of Motion: Inertia
  3. Newton's Second Law of Motion: The Elevator Problem
  4. Newton's Third Law of Motion: Momentum
  5. Energy and Momentum
  6. Concerning Falling Bodies & Projectiles
  7. The Simple Pendulum and Other Oscillating Things
  8. Adventures with Bernoulli: Bernoulli's Principle
  9. Soap Bubbles and Soap Films
  10. Atmospheric Pressure
  11. Centrifugal Force and Other Strange Matters
  12. The Strange Behavior of Rolling Things
  13. Archimedes' Principle
  14. Pascal's Principle: The Properties of Liquids
  15. Levers, Inclines Planes, Geared-wheels and Other Machines
  16. The Ideas of Heat and Temperature
  17. Thermometric Properties and Processes
  18. How to Produce Heat Energy
  19. Thermal Expansion of Stuff: Solids
  20. Thermal Expansion of Stuff: Gases & Liquids
  21. The Strange Thermal Behavior of Ice and Water
  22. Heat Energy Transfer by Conduction
  23. Heat Energy Transfer by Convection
  24. Heat Energy Transfer by Radiation
  25. Evaporation, Boiling, Freezing: A Dramatic Adventure
  26. Miscellaneous Adventures in Heat
  27. The Drama in Real Cold Stuff: Liquid Nitrogen
  28. The Physics of Toys: Mechanical
  29. The Physics of Toys: Acoustic and Thermal
  30. Waves: Kinds of Properties
  31. Sound Waves: Sources of Sound & Pitch and Frequency
  32. Vibrating Bars and Strings: The Phenomenon of Beats
  33. Resonance: Forced Vibrations
  34. Sounding Pipes
  35. Vibrating Rods and Plates
  36. Miscellaneous Adventures in Sound
  37. Electrostatic Phenomena: Foundations of Electricity
  38. Electrostatic Toys, Part 1
  39. Electrostatic Toys, Part 2
  40. Adventures with Electric Charges
  41. Adventures in Magnetism
  42. Ways to "Produce" Electricity
  43. Properties and Effects of Electric Currents
  44. Adventures in Electromagnetism
  45. Further Adventures in Electromagnetism
  46. Miscellaneous and Wondrous Things in E&M

Course Description

Demonstrations in Physics was an educational science series produced in Australia by ABC Television in 1969. The series was hosted by American scientist Julius Sumner Miller, who demonstrated experiments involving various disciplines in the world of physics. The series was also released in the United States under the title Science Demonstrations.

This program was a series of 45 shows (approximately 15 minutes each) on various topics in physics, organized into 3 units: Mechanics; Heat and Temperature / Toys; and Waves and Sound / Electricity and Magnetism.

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