1. Let’s begin by making a few predictions: If the ball pops up out of the column while the “ballistics car” is moving to the left, where will it land? A) In front of the column B) Behind the column C) Back in the column

2. Putt-Putt Golf anyone????

4. How can we explain these observations and ALL other motion around us? First, an observation: It seems obvious that a ________ (a _______ or a ________) is necessary to maintain motion…. This idea that force is needed to maintain motion goes way back to a Greek scientist of the 4 th century BC: ___________. For MANY centuries, physics “slept in his shadow”…… He argued that motion can be divided up into 2 types: __________ and ___________. forcepushpull Aristotle NaturalViolent

5. He believed that the “natural” motion of celestial objects such as the moon, planets, and stars was ________. (Cartoons from “The Cartoon Guide to Physics” by Larry Gonick and Art Huffman) circular

6. He also believed that terrestrial objects, such as rocks, apples, people, etc. tend “naturally” to ______. He further argued that “violent” motion required a _______ to sustain its motion “against nature”. fall force

7. BUT, to see the problem with this logic, we must ask the question: What do objects DO when NO FORCE is acting?

8. To be more specific: What happens to a hockey puck after it has been struck on the ice (and no force is now present)? What happens to a rocket that has headed to the moon after the rocket engines are shut off? It wasn’t until the 16 th Century that __________ argued that ___ ________ is necessary to keep an object moving in a straight line (IF it had initially been moving!) Galileo FORCE NO

9. Aristotle’s ideas had been displaced! Why had it taken so long? It was the force of _____________ that had made it so difficult to see! FRICTION

11. Newton’s 1 st Law of Motion is also called the Law of ________. More formally stated, it says: “Every object continues in its state of rest, or of motion in a _______ _______ at _________ _________, unless a _______ is exerted upon it.” Now can we explain the observations from our initial demonstrations?? Force Constant Speed Straight Line Inertia

12. More Demonstrations or Examples: 1.Seatbelt demonstration Lap Belt Only! Shoulder & Lap Belt! No Seat Belt!

13. 2. Braking and accelerating in a car… Which way do you “move”? Why? 3. Pulling-tablecloth-beneath- dishes “Magic Trick”

14. 4. Tightening a loose hammer head… Hold it which way? 5. Line from the movie Apollo 13: “We just put ___ _____ _____ in the driver’s seat” 6. Roller Coasters 7.Fox Trot Cartoon… OR Sir Isaac Newton

16. The property of objects that makes them “tend” to stay at rest or in motion is called INERTIA. The more inertia an object has, the more ____________ it has to change in its motion. The amount of inertia an object has is measured by its ______. The more “massive” an object, the more inertia it has, so a larger _______ is required to change its motion. vs. resistance mass force

17. So…. What IS Mass? It’s a measure of the amount of ________ or ________ in an object and depends only on the number of and kind of atoms that compose it. Mass is NOT Volume (a measure of space). For example, a small, dense rock can be more “massive” than a large pillow. Mass is NOT Weight (the __________ ____ ___________ on an object. Weight depends on an object’s location. Mass does not. matter material force of gravity

18. For Example, on the moon, where gravity is approximately 1/6 th of earth’s gravity, your _______ would be less, but your ________ would be the same. UNITS: (SI or Metric System) Mass: _____________ Weight: _____________ (English System = __________) On earth, a 1 kg mass weighs ___ N or___ lbs. On the moon, 1 kg weighs about ___ N. weight Pound (lb) Newton (N) Kilogram (Kg)…1 kg =1000 g mass 2.29.8 1.6