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Motion. Motion change in position TPS: List three examples of motion. Be prepared to explain. Be prepared to explain.

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Presentation on theme: "Motion. Motion change in position TPS: List three examples of motion. Be prepared to explain. Be prepared to explain."— Presentation transcript:

1 Motion

2 Motion change in position TPS: List three examples of motion. Be prepared to explain. Be prepared to explain.

3 How do I know if something is in motion? Reference point is a place or object used for comparison to see if something is in motion. Reference Points

4 Forces A force is a push or pull In your notebook list at least 4 examples of force Be prepared to share your answers

5 Balanced and Unbalanced Forces To describe a force, you must know two things: Size of the force and Direction of the force

6 Balanced Forces Forces that are equal in size but opposite in direction Balanced forces do not cause a change in the motion of objects

7 Unbalanced Forces Forces that cause a change in the motion of an object

8 Balanced or Unbalanced? Explain your answer 45 N 45 N 50 N 50 N

9 Unbalanced forces Unbalanced forces can change the motion of an object in two ways:  When unbalanced forces act on an object at rest, the object will move  When unbalanced forces act on a moving object, the velocity of the object will change

10 Work Work: using a force for a distance for a distance W = F x d The work done by forces on an object = changes in energy for that object. Work and Energy are measured in Joules 1 Joule=1 Newton meter

11 42 How much work is performed when a 50 kg crate is pushed 15 m with a force of 20 N? F 300 J G 750 J H 1,000 J J 15,000 J Use the formula Work = Force x distance Force of 20 N x 15 meters = 300 Joules Answer:

12 Energy Is defined as the Ability to do Work So something has energy if it has the ability to do work.( move an object over a distance in the direction of the force) No work: movement is forward, but force on books is upward Work: movement of nail is in direction of force

13 Speed distance traveled per unit of time speed = distance / time speed = distance / time

14 Calculating Speed Distance= Speed X Time Speed = Distance Time Time = Distance Speed Write these in your notebook

15 Which formula? Work with a partner to decide what formula you would use with each of these problems: Work with a partner to decide what formula you would use with each of these problems: A car drives 30 miles in 2 hours. Calculate the car's speed. How far would you travel at 80 km / hr for 5 hours? How long would it take to go 250 miles at a speed of 50 miles / hour? Be prepared to share your answers Be prepared to share your answers

16 Demonstrate that changes in motion can be graphically represented

17 What does it show? Firstly, look at the axis to see what the graph represents.

18 Drawing graphs of real-life situations In your exams you may be asked to complete, or draw, graphs to represent given situations.

19 Plot a distance time-graph to represent your journey to and from the club. You are at home getting ready to go out to your stamp collecting club. You leave your house and jog the 1000m to the club. You arrive 5 minutes later. You exchange stamps and chat for 1 hour, then leave for home. It takes you 10 minutes. Example 1.

20 1.Choose a suitable scale for each axis. You are at home getting ready to go out to your stamp collecting club. You leave your house and jog the 1000m to the club. You arrive 5 minutes later. You exchange stamps and chat for 1 hour, then leave for home. It takes you 10 minutes. Distanc e from home (m) Time (minutes) 200 400 600 800 1000 0 10 20 30 40 50 60 70 80 2. Decide how many points to plot. You are at home getting ready to go out to your stamp collecting club. You leave your house and jog the 1000m to the club. You arrive 5 minutes later. You exchange stamps and chat for 1 hour, then leave for home. It takes you 10 minutes. 3. Draw the graph with suitable accuracy 4. Provide a title and label the axis The journey to and from my stamp collecting club Drawing graphs of real-life problems

21 Velocity Velocity Speed and direction Velocity describes the speed and direction of a moving object

22 Speed or Velocity? Read the following and work with a partner to decide if the following represent “Speed” or “Velocity” Read the following and work with a partner to decide if the following represent “Speed” or “Velocity” airplane moving towards the west with a speed of 482 km/hr car moving at 80 km/hr Be ready to explain your answers Be ready to explain your answers

23 Changes in Speed Speeding up and slowing down are changes in speed

24 Acceleration Change in speed or direction An object is accelerating when it speeds up, slows down, or changes direction

25 Acceleration 3 Examples: Case 1 – Interval increases because car is moving faster and faster Case 2 – Interval decreases because car is slowing down Case 3 – Interval stays the same, but direction of motion is constantly changing

26 Acceleration Slowing down is sometimes called deceleration TPS: work with a partner to explain why coming to a stop at a traffic light is acceleration. Be ready to share your answer Be ready to share your answer

27 Newton’s First Law of Motion Newton’s First Law of Motion states that an object will remain at rest, or move at a constant speed in a straight line, unless it is acted on by an unbalanced force

28 Newton’s First Law of Motion inertia – tendency of an object to stay at rest or in motion Newton’s First Law of Motion is also called the Law of Inertia Newton’s First Law of Motion is also called the Law of InertiaLaw of InertiaLaw of Inertia Watch this animation, then TPS to explain why is it important to wear seatbelts when riding in a car. Be prepared to share your thoughts with the class.

29 After watching the film clip, quickly sketch this drawing in your notebook. Add a seatbelt to the driver. Use another arrow to show the force that the seatbelt exerts to prevent the man from flying out of the car Newton’s First Law in action!

30 Now check your sketch by watching this film clip: Car Crash Car Crash Do you need to make any changes to your sketch? If so, do it now. Write a paragraph to describe how seatbelts and car crashes are related to Newton’s First Law of Inertia.

31 Newton’s Second Law of Motion Newton’s Second Law of Motion Newton’s Second Law of Motion describes the relationship among force, mass, and acceleration Newton’s Second Law of Motion Watch this clip and then TPS to explain what can cause the elephant to move faster. Watch this clip and then TPS to explain what can cause the elephant to move faster.

32 Newton’s Second Law of Motion Unbalanced forces cause objects to accelerate The amount by which an object accelerates depends on two things  Size and direction of the force  Mass of the object

33 Newton’s Second Law of Motion If two forces act on the same object, the larger force will produce more acceleration than the smaller force

34 Newton’s Second Law of Motion If you apply the same amount of force to two objects with different masses, the object with the smaller mass will accelerate more than the object with the larger mass

35 TPS to discuss: How can you apply a force to two objects with different masses, but still have them accelerate at the same rate?

36 Newton’s Second Law of Motion force = mass X acceleration F = m x a F = m x aF = m x aF = m x a Force is measured in Newtons (N) Newton – unit of force equal to one kilogram-meter per second per second

37 Newton’s Third Law of Motion Newton’s Third Law of Motion states that for every action force, there is an equal and opposite reaction force

38 Newton’s Third Law of Motion Forces always act in pairs The two forces act in opposite directions

39 Newton’s Third Law of Motion action force – force acting in one direction reaction force reaction force – force acting in the opposite direction (scroll down to boat animation) reaction force Watch the animation, then TPS to explain why the boat moved away from the dock. Watch the animation, then TPS to explain why the boat moved away from the dock.

40 Review Match the following to the Newton’s Law that explains the motion in each picture 1 St Law ? 2 nd Law? Or 3 rd Law?


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