January 5, SWBAT explain Newton s first law by describing it in a series of examples.

Transcription

1 January 5, 2017 Aims: SWBAT explain Newton s first law by describing it in a series of examples. Agenda 1. Do Now 2. Class Notes 3. Guided Practice 4. Independent Practice 5. Practicing our AIMS: Homework: F.2 Newton s 1 st Law How will you help our class earn all of our S.T.R.I.V.E. Points? 100% HW Club: You in? 1

2 Aim Check: 2

3 SCIENCE 8 Newton s 1 st Law F.2 Name: Date: Homeroom: Forces Telekinesis, wingardium leviosia, the force ALL SCIENCE! OBJECTIVES: By the end of class, students will be able to SWBAT explain Newton s first law by describing it in a series of examples. DO NOW Directions: 47% of our class chose A. Explain the misconception our class had about acceleration. Then, select the correct answer and justify your reasoning. 1. When an object accelerates then stops accelerating, what happens to the object? A. It slows down B. It continues to moves at a constant velocity C. It goes faster D. It stops completely 3

4 MEET SIR ISSAC NEWTON CLASS NOTES Born in England, Isaac Newton was a highly influential physicist, astronomer, mathematician, philosopher, alchemist and theologian. DID YOU KNOW? An Apocalyptic Prediction Newton loved science, but he also regularly studied the Bible. Many of his writings, in fact, are more about philosophy and religion than they are about science. He often studied the Bible to find inklings of inspiration. In one of his papers, he even predicted that the end of the world would happen in the year The Dog Did It Newton is one of the few people who can actually claim a dog ate his homework. His beloved pooched burned down his lab one day, although some believe the story was invented to cover the fact that Newton himself managed to torch his own work area. 3. Credit the Bully Newton was not really fond of school. One day, however, a bully came his way and beat him up. Newton vowed to get even, so he challenged the bully to a fight and wound up winning. Then he decided that being physically better wasn t good enough. He focused on his studies so that he could intellectually defeat this bully as well. 4. A Calculated Effort Newton is often credited with the invention of Calculus, but a German mathematician named Gottfried Leibniz also claimed credit. The Royal Society eventually concluded that Leibniz had no claim on Calculus and that Newton was the true inventor. Who wrote the concluding comments that discredited Leibniz? Newton, of course. 5. Popular Tools In 1668, Newton developed what would become his most famous invention: the reflecting telescope. The technology that he developed is still regularly used today by amateur astronomers who want to see more of the stars than the human eye can see. 4

5 NEWTON S FIRST LAW OF MOTION NEWTON S 1 st LAW: A force is a o It is a quantity and cares about An force means an outside force is being put on the object. Objects move only if the is not. o The of all forces acting on an object is called the net force. When all the forces on an object are balanced, the object is in. o When an object is in equilibrium it means it will continue its This is why it s important to draw a picture! So we can figure out what the net force is (forces are vectors so direction is important!) Example: What is the net force on a book with 30 N of gravity pulling it down and 10 N of air resistance pushing it up? 5

6 INERTIA: o Inertia is determined by an object s o Mass is the amount of in an object and measured in o Mass is o The more mass an object has, the its inertia, and the force it takes to change its state of motion. THE REASONS YOU WILL GET THIS LAW WRONG! FRICTION: Causes of Friction The strength of the force of friction depends on two factors: o o Circle the surface that will produce more friction Friction acts in a direction to the direction of the object s motion. GRAVITY: WEIGHT: o Acts everywhere in the universe o The strength of the force of gravity depends on two factors: 6

7 WE DO: Guided Practice 7

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9 YOU DO: Independent Practice Directions: For each key term, explain the big idea to a kindergartener. Then, draw a picture to illustrate the word. Term Concept Picture NEWTON S FIRST LAW INERTIA FRICTION GRAVITY 9

10 1. Imagine a place in the cosmos far from all gravitational and frictional influences. Suppose that you visit that place and throw a rock. The rock will a. gradually stop. b. continue in motion in the same direction at constant speed. 2. A 2-kg object is moving horizontally with a speed of 4 m/s. How much net force is required to keep the object moving at this speed and in this direction? 3. Fred spends most Sunday afternoons at rest on the sofa, watching pro football games and consuming large quantities of food. What affect (if any) does this practice have upon his inertia? Explain. 4. Ben Tooclose is being chased through the woods by a moose that he was attempting to photograph. The enormous mass of the moose is extremely intimidating. Yet, if Ben makes a zigzag pattern through the woods, he will be able to use the large mass of the moose to his own advantage. Explain this in terms of inertia and Newton's first law of motion. 10

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13 Science 8 Name: SKILL SNAPSHOT Date: Homeroom: F.2: Newton s 1 st Law Quick Notes: Read and ANNOTATE the information before you solve the problem. Like A Scholar? Yes No Redo? Yes No Directions: Support your selection by finding evidence to support your answer OR evidence to support why another is incorrect. Be sure to include at least one scientific term in your evidence Question 1. Which term is an example of force? Supporting evidence A. energy B. mass C. weight D. work 2. What is a net force? A. The total of all the force B. A force you apply using a net C. How strong a force is D. What direction the force is pointing at 3. It is more difficult to start a 50-kg box sliding across the floor than a 5-kg box because the 50-kg box has greater A. size B. inertia C. volume D. velocity 4. A student applies a constant force to the pedals of a bicycle to travel at a constant speed on a calm day. Suddenly, a strong gust of wind blows straight toward the front of the student. Which statement describes the motion of the student on the bicycle immediately after the wind started to blow. If the student continues to apply the same constant force to the pedals? A. The motion sped up. B. The motion reversed. C. The motion slowed down. D. The motion remained constant. 13

14 9. According to Newton s first law of motion, what will happen to the soccer ball? Justify your reasoning using scientific key terms. Claim (1/2 pt.) Evidence (1 pt.) Error Free (1/2 pt.) Correct conclusion Relevant Evidence Complete Sentence Punctuation Capitalization Clarity 10. How would increasing the soccer ball s mass change the picture? Justify your reasoning using scientific key terms. Claim (1/2 pt.) Evidence (1 pt.) Error Free (1/2 pt.) Correct conclusion Relevant Evidence Complete Sentence Punctuation Capitalization Clarity 14