1. Activator Write the question and answer:
What do you think of when you hear the word “force?”

2. Force
SPS8. Students will determine relationships among force, mass, and motion.
b. Apply Newton’s three laws to everyday situations by explaining the following: Inertia; Relationship between force, mass and acceleration; Equal and opposite forces c. Relate falling objects to gravitational force
d. Explain the difference in mass and weight.

3. Force
Definition
Any push or pull that could cause a change in motion.

4. Force Examples Applied Frictional Electrostatic Magnetic Gravitational
Nuclear
Normal

5. Net Force
Definition
The sum of all the forces in a system

6. Net Force Examples Sitting in a chair – net force = 0
Playing tug of war and team A pulls with 100 N, the team B pulls with 75 N – net force = 25 N in the direction of team A

7. Balanced Forces Definition
A condition when opposite forces acting on an object are equal. The net force acting on the object is zero.

8. Balanced Forces Example
A car engine is applying a forward force 400 N and the friction acting against the car is 400 N. The forces acting on the car are balanced and the speed does not change.

9. Unbalanced Forces Definition
A condition when opposite forces acting on an object are not equal. The net force acting on the object is not zero.

10. Unbalanced Forces Example
A car engine is applying a forward force 800 N and the friction acting against the car is 400 N. The forces acting on the car are unbalanced and the speed of the car is changing.

11. Speed
Definition
The distance an object travels during an amount of time

12. Speed
Example
The speedometer in a car shows the speed of the car.

13. Velocity
Definition
The speed and direction in which an object is moving

14. Velocity
Example
You are traveling 70 miles per hour northeast on the interstate

15. Acceleration Definition
The rate at which an object’s velocity (speed) is changing over time.

16. Acceleration
Example
A 2015 LaFerrari can go 0 mi/h to 60 mi/h in 2.4 sec

17. Gravity
Definition
A force of attraction between all objects with mass

18. Gravity
Example
Objects falling toward Earth

19. Weight
Definition
The force of gravity acting on an object

20. Weight
Example
Measured by a scale

21. Inertia
Definition
The property of an object to resist change in motion.

22. Inertia
Example
A bucket full of sand is harder to push than an empty bucket

23. TOTD
Explain how each of the vocabulary words we covered today were demonstrated in the bowling ball activity.

24. Activator Write the question and answer:
How does a person win an arm wrestling game (balanced or unbalanced forces)? Why?
I will ask for volunteers to arm wrestle after we finish the activator.

25. Force Diagrams
GPS8
Students will determine the relationships among force, mass, and motion.

26. Force Diagram
A simple drawing that shows the forces acting on an object. The object is represented by a box. The direction of the forces acting on the object are represented by arrows.

27. Force Diagram
Example

28. Match the following descriptions with the forces identified on your handout:
Force from a solid surface that acts opposite to gravity.
Force applied through a rope.
Force resisting motion.
A push or a pull acting on an object.
Force pulling all objects to the center of Earth.

29. Practice 1
A book is at rest on a tabletop. FN Fg

30. Practice 2
A flying squirrel is gliding (no wing flaps) from a tree to the ground at constant velocity. Consider air resistance.
Fair Fg

31. Practice 3 FN Ff Fapplied Fg
A rightward force is applied to a book in order to move it across a desk with a rightward acceleration. Consider frictional forces. Neglect air resistance. FN Ff
Fapplied Fg

32. Practice 4
A skydiver is descending with a constant velocity. Consider air resistance.
Fair Fg

33. Practice 5
A car is coasting to the right and slowing down. FN Ff Fg

34. Practice 6
An egg is free-falling from a nest in a tree. Neglect air resistance. Fg

35. Practice 7 FN Ff Fapplied Fg
A rightward force is applied to a book in order to move it across a desk at constant velocity. Consider frictional forces. Neglect air resistance. FN Ff
Fapplied Fg

36. Activator Define the following forces in your own words. Applied Force
Frictional Force
Normal Force
Gravitational Force
Tensional Force
Air Resistance Force

37. Diagram/Describe the Forces Acting Upon the Object
A bicycle is parked in a driveway. Diagram the forces acting on the bicycle.

38. Diagram/Describe the Forces Acting Upon the Object
A car engine is applying a forward force 400 N and the friction acting against the car is 400 N.

39. Diagram/Describe the Forces Acting Upon the Object
A gymnast is holding onto a rope that is attached to the ceiling and she is motionless. Diagram the forces acting on the girl as she holds on to the rope.

40. Diagram/Describe the Forces Acting Upon the Object
An apple is free-falling from a tree. Neglect air resistance. Diagram the forces acting on the apple as it falls.

41. Diagram/Describe the Forces Acting Upon the Object
A car engine is applying a forward force 800 N and the friction acting against the car is 400 N.

42. Diagram/Describe the Forces Acting Upon the Object
An egg is falling (not freely, do not neglect air resistance) from a nest in a tree. Diagram the forces acting on the egg as it falls.

43. Diagram/Describe the Forces Acting Upon the Object
A leftward force is applied to a cellphone in order to move it across a desk with a rightward acceleration. Consider frictional forces. Neglect air resistance. Diagram the forces acting on the cellphone.

44. Diagram/Describe the Forces Acting Upon the Object
A car is stopped at a stop light.

45. Diagram/Describe the Forces Acting Upon the Object
A skydiver is descending with a constant velocity. Consider air resistance. Diagram the forces acting upon the skydiver.

46. Diagram/Describe the Forces Acting Upon the Object
A car is parked on a sloped street.

47. Diagram/Describe the Forces Acting Upon the Object
A hot air balloon is accelerating upward, neglect air resistance.

48. Diagram/Describe the Forces Acting Upon the Object
A car is coasting to the right and slowing down. Diagram the forces acting upon the car.

49. Calculate the net force
5 + 5 = = = = 10 15 5

50. Calculate the net force
Fnet is 400 N, up

51. Calculate the net force
Fnet is 200 N, down

52. Calculate the net force
Fnet is 20 N, left