1. Newton’s 1st Law: More Practice

2. Newton’s 1st Law: More Practice

3. Newton’s 1st Law: More Practice

4. Newton’s 1st Law: More Practice

5. Newton’s 1st Law: More Practice

6. Newton’s 1st Law: More Practice

7. Newton’s 1st Law: More Practice

8. Newton’s 1st Law: More Practice

9. Newton’s 1st Law: More Practice

10. Newton’s 2nd Law of Motion: Student Learning Goal
The student will be able to state Newton’s 2nd Law and apply it in qualitative and quantitative terms to explain the effect of forces acting on objects. (B3.4)

11. Newton’s 2nd Law of Motion

12. Newton’s Second Law of Motion
If the net force is not zero, the object will be accelerated in the direction of the net force.

13. Newton’s Second Law of Motion
If the net force is not zero, the object will be accelerated in the direction of the net force.

14. Newton’s Second Law of Motion
If the net force is not zero, the object will be accelerated in the direction of the net force.
i.e. the more massive the object, the harder it is to change its motion (the higher its inertia).

15. Newton’s Second Law of Motion
If the net force is not zero, the object will be accelerated in the direction of the net force.

16. Newton’s Second Law Example
Example: A weightlifter lifts a 165-kg weight by exerting a force of 1.8 kN [up]. The force of gravity on the object is 1.6 kN [down]. Draw a FBD of the weight. What is the net force on the weight? What is the acceleration of the weight?

17. Newton’s Second Law Example
FA = 1.8 kN
Fg = 1.6 kN

18. Newton’s Second Law Example
The net force is 0.2 kN [up].
FA = 1.8 kN
Fg = 1.6 kN

19. Newton’s Second Law Example
What is the acceleration of the weight?

20. Newton’s Second Law Example
What is the acceleration of the weight?

21. Newton’s Second Law Example
What is the acceleration of the weight?

22. Newton’s Second Law Example
What is the acceleration of the weight?

23. Newton’s Second Law Example
What is the acceleration of the weight?

24. Newton’s Second Law Example
What is the acceleration of the weight?
[up]

25. Example with the Equations of Motion
A car is travelling at 25 m/s [forward] when the driver slams on the brakes and stops the car in 3.0 s. Calculate (a) the acceleration of the car and (b) the net force needed to cause that acceleration if the mass of the car is 1200 kg.

26. Example with the Equations of Motion
A car is travelling at 25 m/s [forwards] when the driver slams on the brakes and stops the car in 3.0 s. Calculate (a) the acceleration of the car.

27. Example with the Equations of Motion
A car is travelling at 25 m/s [forwards] when the driver slams on the brakes and stops the car in 3.0 s. Calculate (a) the acceleration of the car.

28. Example with the Equations of Motion
A car is travelling at 25 m/s [forwards] when the driver slams on the brakes and stops the car in 3.0 s. Calculate (a) the acceleration of the car.

29. Example with the Equations of Motion
A car is travelling at 25 m/s [forwards] when the driver slams on the brakes and stops the car in 3.0 s. Calculate (a) the acceleration of the car.

30. Example with the Equations of Motion
A car is travelling at 25 m/s [forwards] when the driver slams on the brakes and stops the car in 3.0 s. Calculate (a) the acceleration of the car.
or 8.3 m/s2 [backward]

31. Example with the Equations of Motion
Calculate (b) the net force needed to cause that acceleration if the mass of the car is kg.

32. Example with the Equations of Motion
Calculate (b) the net force needed to cause that acceleration if the mass of the car is kg.
or N [backward]

33. Weight
The formula F = ma can also be used to calculate the weight Fg of an object

34. Weight
The formula F = ma can also be used to calculate the weight Fg of an object, the magnitude of the force of gravity acting on it

35. Weight
The formula F = ma can also be used to calculate the weight Fg of an object, the magnitude of the force of gravity acting on it, if the acceleration a is . . .

36. Weight
The formula F = ma can also be used to calculate the weight Fg of an object, the magnitude of the force of gravity acting on it, if the acceleration a is the acceleration due to gravity, g = 9.8 m/s2.

37. Weight
The formula F = ma can also be used to calculate the weight Fg of an object, the magnitude of the force of gravity acting on it, if the acceleration a is the acceleration due to gravity, g = 9.8 m/s2.
(mass is measured in kg)

38. Weight Weight is therefore measured in Newtons.
And the direction of the force is always [down].

39. Weight: Example
What is the weight of a 140 kg person?

40. Weight: Example
What is the weight of a 140 kg person?

41. Weight: Example
What is the weight of a 140 kg person?

42. More Practice
Tomorrow:
Newton’s 2nd Law of Motion Lab