Monday, September 22 nd

Transcription

1 Monday, September 22 nd Entry Task Schedule: Force & Inertia Notes From your notes, what are the three types of forces described in your textbook? Objective: I will explain that inertia is a measure of mass Homework Read the inertia activity carefully Please have on desk: Chapter 11 Vocabulary

2 Forces Force is a push or a pull Forces move things, stop things, speed things up, slow things down, and change their direction. Forces are measured in Newtons FORCES CHANGE MOTION

3 1. Read Types of Forces on page 346. Write a description of the three types of forces in your own words.

4 Types of Forces Contact Force One object pushes directly on another. Example The skydiver pushes himself out of the plane with his hands and feet

5 Types of Forces Gravity A force of attraction between 2 things with mass. Example Gravity of earth and the skydivers pull towards each other.

6 Types of Forces Friction A force that resists motion when two surfaces are pressed together. Example The parachute increases the air resistance (friction between the air and an object) of the skydiver.

7 2. Read page 347 and explain how the terms NET FORCE, BALANCED FORCE, and UNBALANCED FORCE are related

8 Balanced and Unbalanced Forces Forces have both SIZE and DIRECTION If net force is NOT ZERO (unbalanced), the object s motion will change. If net force is zero (balanced), the object s motion does not change.

9 Forces Balanced or Unbalanced For each picture, identify whether the forces acting on the object are balanced or unbalanced Give at least one reason for your answer. You can think about what happened before the picture was taken and think about what will happen after the picture was taken

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17 What is inertia? Inertia is the tendency of an object to remain at rest if it's already at rest, or to keep moving if it's already moving. Tablecloth trick: Too little force, too little time to overcome "inertia" of tableware

18 Examples of inertia

19 Newton s First Law of Motion Motion tends to continue unchanged. The elephant at rest tends to remain at rest.

20 Forces on Moving Objects Read pg Answer Check your reading questions (pg 348, 349 & 351) Put all answers in comp. book

21 Answers to Check your Reading Pg 348 If all forces on an object are balanced, than motion does not change (same speed and direction). Pg 349 Galileo believed that it takes a force to change motion of an object; Greeks believed that an object stays in motion only if a force continues to act on it Pg 351 If a car makes a sudden stop, the passenger continues to move forward. Seatbelts are designed to safely stop the motion of the passenger

22 Tuesday, September 23 rd Entry Task 1. Draw a diagram of yourself shooting a basketball at the net. Label all of the forces acting on the ball. Schedule: Inertia Activity Objective: I can demonstrate Newton s 1 st law of motion 2. Explains what happens if you use the right amount of force but in the wrong direction. Homework: Complete Inertia Activity Please Have on Desk: Inertia activity

23 Wednesday, September 24 th Entry Task Explain how inertia and mass are related. Schedule: Force review Newton s 2 nd law of motion Objective: I can understand that force and mass determine acceleration Homework: Re-read 11.1 and 11.2 Please have on desk: Inertia activity, textbook, journal

24 Newton s 2 nd Law of Motion Newton s Second Law of Motion states that the acceleration of an object increases with increased force and decreases with increased mass. It also states that the direction in which the object accelerates is the same as the direction of the force.

25 Newton s 2 nd Law Formula You can calculate the force, the mass, or the acceleration if you know two of the three factors. The formula for Newton s second law is Force = mass acceleration or F = ma

26 What are the units? newton (N) is the unit for force kilogram (kg) is the unit for mass m is the unit for acceleration s 2 A newton (N) = 1kg m s 2

27 1. What force is needed to accelerate a 10 kg shopping cart 3 m/s 2? You try this!

28 You try this! 2. If a team pulls with a combined force of 9000 N on an airplane with a mass of 30,000 kg, what is the acceleration of the airplane?

29 3. A model rocket is accelerating at 2 m/s 2. The force on it is 1 N. What is the mass of the rocket? You try this!

30 Thursday, September 25 th Entry Task Explain what you must do to increase the acceleration of an object. Schedule: Review 11.2 Newton s Second Law Math Practice Objective: I can calculate force, acceleration, and mass when given the other two variables Homework Complete Math handouts Please have on desk: Calculator, pencil

31 Entry Task Friday, September 26 th 1.Restate Newton s 1 st law of motion. 2.Give an example to illustrate Newton s 1 st law of motion. Schedule: Newton s Laws of Motion Foldable (we will work on this again on 10/1) Objective: I can state Newton s Laws of Motion Homework Complete first two laws on the foldable if not finished in class. Please have on desk: Newton s 2 nd law math

32 You will create a foldable that explains and illustrates Newton s three laws of motion. Your foldable must have an overall theme. Ex: a type of sport, nature activity, hobby

33 1. Determine your theme. Complete the front of your foldable. 2. For each of Newton s laws of motion, - write the law at the top of the page - draw, label, and color a drawing that illustrates this law. Your drawing must follow the theme you chose - explain HOW your drawing illustrates that particular law of motion

34 Explanation clearly shows understanding of law; written law included Drawings are original neat and colored; clearly match explanation Explanation shows knowledge of law, but not understanding; written law included Drawings are not original, but neat and colored; do not clearly match explanation Explanation show limited knowledge of law; written law not included Drawings are not original, messy and not colored; no match to explanation