1. Warm Ups

2. Mini Quiz: In PEN w/ no cross outs!
13) What is the y component
of the applied force?
a) 17.2N b) 21.7N
c) 25N d) 12.5N
14) What is the x component of the following vector:
a) 5.0N b) 9.6N
c) 13.0N d) 28.9N
25N
30°
15N
30°

3. Mini Quiz: In PEN w/ no cross outs! **13 & 14 = A
15) What additional forces are necessary to bring the following object into a state of equilibrium?
a) 20N North 20N east
b) 20N South 20N east
c) 20N North 20N east
d) 20N South 20N west
16) In which case is the tension of the string the greatest?

4. Mini Quiz: In PEN w/ no cross outs!
17) If the sum of all the forces acting on a moving object is zero, the object will:
Slow down and stop
Change the direction of motion
Accelerate uniformly
Continue moving with constant velocity

5. Forces Introduction
1) A force is a push or a pull applied to an object. 2) Definition of Net Force: The vector sum of all the forces on an object (direction determined + or -)

6. Forces Introduction
Equilibrium
When the net forces on an object equals zero, that object is in equilibrium
At equilibrium, an object is either at rest or moving with a constant velocity

7. Forces Introduction
How do I tell if an object is in equilibrium:
Net force = 0N
Constant velocity
No motion

8. * θ = Angle from the horizontal*
Forces Introduction W
Weight (Gravity): Always directly downward.
W = mg
m = mass g = gravity FN
Normal: A surface pushes perpendicular against an object.
FN is Equal and Opposite of the sum of all downward forces Ff
Friction: A force that prevents/goes against (dampens) motion
Will change depending on the surface. FT
Tension: A PULL in the direction of a rope or a wire
Pulled Object: Value will be given
Hanging: FT is Equal and Opposite of the sum of all downward forces F
Applied Force: A force can be a push or pull applied to an object
Fx = Fcos(θ)
Fy = Fsin(θ)
* θ = Angle from the horizontal*

9. Forces Introduction
How to Solve Equilibrium Problems: 1. Find the Net Force of the left-right forces (X) 2) Find the net force of the up-down forces (Y) 3)Remember that the net force = zero

10. Forces WHITEBOARDS
For each of the following questions, determine the net force. You must SHOW YOUR WORK for each question X Y
NET FORCE Vector

11. For the following slides:
1) Find the NET FORCE
This means you find the sum of the forces acting on the object. Watch out for the direction. Left = (-) and right = (+). Up = (+), down = (-)

12. Forces WHITEBOARDS

13. Forces WHITEBOARDS

14. Forces WHITEBOARDS

15. Forces WHITEBOARDS
30N
30
15N

16. *write on back* 1st Law: Law of inertia
An object at rest will stay at rest unless acted on by an outside force
Inertia: The amount of mass an object has
More inertia = more mass = Harder to move

17. 1st Law: Law of inertia
Who does Cam want for his offensive line? WHY?

18. 1st Law: Law of inertia
Whiteboards

19. 1st Law: Law of inertia

20. 1st Law: Law of inertia

21. 1st Law: Law of inertia

22. 3rd Law: Equal and Opposite
For every action, there is an equal and opposite reaction.
“Things push back”

23. 3rd Law: Equal and Opposite The SF player hits the N. O
3rd Law: Equal and Opposite The SF player hits the N.O. player with a force of 50N. Which player will get a concussion? WHY?

24. 3rd Law: Equal and Opposite

25. 3rd Law: Equal and Opposite

26. 3rd Law: Equal and Opposite

27. F = ma 2nd Law: Unbalanced NET Force = Acceleration F - Newtons (N)
Net Force causes acceleration (change in velocity)
UNITS:
F - Newtons (N)
m - kilograms (kg)
a - meters per second squared (m/s2)

28. F = ma 2nd Law: Unbalanced Force = Acceleration
A 40N force is applied eastward to a 10kg object. What is the acceleration and direction of the objects acceleration?
4m/s2 east

29. 2nd Law: Unbalanced Force = Acceleration
F = ma
7500N

30. 2nd Law: Unbalanced Force = Acceleration
F = ma

31. 2nd Law: Unbalanced Force = Acceleration

32. 2nd Law: Unbalanced Force = Acceleration

33. 2nd Law: Unbalanced Force = Acceleration