Chapter 3—Newton’s 1st Law PDF

Chapter 3 Newton’s First Law Main Idea: Forces Cause Δ in Motion  Historical O Aristotle: 4th Century BC O Natural Motion O Straight up or down O Heavy –fall—rock O Light– float– smoke O Circular—normal in space so no force is necessary O...

Chapter 3 Newton’s First Law Main Idea: Forces Cause Δ in Motion  Historical O Aristotle: 4th Century BC O Natural Motion O Straight up or down O Heavy –fall—rock O Light– float– smoke O Circular—normal in space so no force is necessary O Violent O Imposed motion O Push or pull—tug of war, ship;wind O External cause O Clearly the Earth did NOT move!!!!  Copernicus O 1473-1543 O Heliocentric Theory O Worked in Secret  Galileo 1564-1642 O Supported Copernicus…put on trial and under house arrest for heresy (1633-1642) O Force and Friction are his ideas O Only when friction is present is a force needed to keep an object moving  Don’t Stare at the Sun O Galileo went blind from years of studying planets and movement O Discovered LOTS of science O Pendulum, astronomy, speed of light, etc.  One of the first steps of John Paul's papacy, which began in 1978, was to begin procedures leading to the rehabilitation in 1992 of Galileo, the Italian astronomer persecuted by the Church for teaching that the Earth revolved around the sun. The Inquisition condemned Galileo in 1633 because his teachings clashed with the Bible, which read: "God fixed the earth upon its foundation, not to be moved forever." Galileo was rehabilitated after 359 years.  Newton 1642-1727 O Born December 25 1642—or??? premature…the year Galileo died O Developed his laws of motion by the age of 24 O Developed Calculus  Inertia O OBJECT’S RESISTANCE TO CHANGE  st Newton’s 1 Law O Every object continues in straight line at a uniform speed or at rest unless acted on by a nonzero net force O Force is needed to overcome friction but an object will move indefinitely in a force free environment. O PUT IT INTO YOUR OWN WORDS!!!!  Inertia Seatbelts  Examples As you watch the following clips think about: WHERE IS INERTIA? HOW IS NEWTON’S 1st LAW BEING SHOWN? WHAT EFFECT DOES MASS HAVE ON THE OUTCOME? OReggie Bush OCar Crash Ice OCorvette OKids  Mass Versus Weight O Mass: quantity (amount) of MATTER in an object O Measure of inertia “laziness” kilograms (grams) O Weight: force of gravity on an object O Newtons (N) (m/s2 x kg) O Moon = 1/6E O Volume: measure of space O cm3 or Liters How much do you weigh? O Conversion from mass to weight O 1 kg = 9.8N O 1 kg = 2.2 lbs O w = mg So 100 lbs on EARTH has a weight of ? 100 lbs x 1 kg x 9.8 N = 445 N 2.2 lbs 1 kg  More Mass/Weight O How much would a 30 kg mass weigh on Earth? O The Moon? O Jupiter (g=25m/s2) Which one of these has more mass? O 20 N on Earth versus 20 N on the Moon? O 12 kilograms of sugar or 12 kilograms of lead?  Mass on other planets! Gravity on other planets Crushing Cars with the same box… on different planets. Your weight on other planets Calculator How much would you weigh?  Moving Earth O If the plane hovers above the ground does the Earth move on without it?