1. Force, Motion, and Design Quarter 2 1

2. What will we learn? The students will be able to describe how different forces (friction, gravity, and change in mass) change the motion of the object.  5.P.1. Understand force, motion and the relationship between them.  5.P.1.1 Explain how factors such as gravity, friction, and change in mass affect the motion of objects. The students will be able to describe how different forces (friction, gravity, and change in mass) change the motion of the object.  5.P.1. Understand force, motion and the relationship between them.  5.P.1.1 Explain how factors such as gravity, friction, and change in mass affect the motion of objects. 2

3. Motion an object's change in position relative to a reference point over a period of time 3

4. PUSH OR PULL = FORCE 4

5. Two Types of Forces Balanced forces = they balance each other out, so there is no change in motion Unbalanced forces = one force is stronger than the other, so motion occurs Balanced forces = they balance each other out, so there is no change in motion Unbalanced forces = one force is stronger than the other, so motion occurs 5

6. Balanced Forces 6 BALANCED FORCES SAME Net force No change in motion UNBALANCED FORCES One force is stronger than the other Change in motion

7. 7 UNBALANCED FORCES

8. Balanced or Unbalanced  Sometimes forces are shown with vectors (arrows). A longer arrow means a greater force.  Pictured below:  Balanced or unbalanced?  Which direction would the object move?  Sometimes forces are shown with vectors (arrows). A longer arrow means a greater force.  Pictured below:  Balanced or unbalanced?  Which direction would the object move? 8

9. Net Force When more than 1 force acts on an object, the forces combine to form a net force. *opposite direction: subtract the Newtons *same direction: add the Newtons When more than 1 force acts on an object, the forces combine to form a net force. *opposite direction: subtract the Newtons *same direction: add the Newtons 9

10. Practice Calculating Net Force 10

11. Practice Calculating Net Force John’s class is competing against Ms. Guerrero’s class in tug-of-war at Laps for Holly Grove. John’s class is pulling with 250 Newtons and Ms. Guerrero’s class is pulling with 550 Newtons. Who will win the game? Draw a picture of the scenario and calculate the net force. 11

12. What is gravity? FORCE OF GRAVITY=GROUND FORCE 12 Gravity is a forces that PULLS us towards the earth.

13. Gravity continues pulling 13 Ground also pushes

14. FALLING OBJECTS  STOP MOVING WHEN 14 BALANCED FORCES AIR Resistance is the force of air friction on the object.

15. Why do things eventually slow down or stop moving. 15

16. FRICTION OPPOSES MOTION 16 Friction pair= tires and road surface CAR AT REST Friction pair= grass surface and ball GOLF BALL NOT MOVING MOVING SKATES Objects stops when all forces are balanced Friction

17. FRICTION 17 CARPET SIDEWALK DIRT SURFACE SURFACE WITH LESS FRICTION ?

18. Energy – the ability to do work/move KineticPotential Moving energyStored energy 18

19. Acceleration rate of increase or decrease of speed and/or a change in velocity 19

20. Momentum force or speed of movement; mass in motion 20

21. Clicker questions  #1 What force opposes (tries to stop) motion?  A) gravity  B) friction  C) inertia  D) momentum  #1 What force opposes (tries to stop) motion?  A) gravity  B) friction  C) inertia  D) momentum 21

22. Clicker questions  #2 Which surface would have the MOST friction?  A) a smooth road  B) an icy sidewalk  C) a tile floor  D) a grass field  #2 Which surface would have the MOST friction?  A) a smooth road  B) an icy sidewalk  C) a tile floor  D) a grass field 22

23. Clicker questions  #3 Which of the following is an example of a balanced force?  A) When you sit on the ground, gravity pulls you down, but the floor pushes you up  B) When a truck takes off from a stoplight and overcomes the force of gravity.  #3 Which of the following is an example of a balanced force?  A) When you sit on the ground, gravity pulls you down, but the floor pushes you up  B) When a truck takes off from a stoplight and overcomes the force of gravity. 23

24. Clicker questions  #4 Which of the following statements about gravity is true?  A) Gravity is a force that pushes us towards the ground.  B) Gravity is a force that pushes us upwards.  C) Gravity is a force that pulls us toward the ground.  D) Gravity is a force that pulls us upwards.  #4 Which of the following statements about gravity is true?  A) Gravity is a force that pushes us towards the ground.  B) Gravity is a force that pushes us upwards.  C) Gravity is a force that pulls us toward the ground.  D) Gravity is a force that pulls us upwards. 24