1. Chart on page 2 of your notes!
Do Now
Chart on page 2 of your notes!

2. Net Force = mass x acceleration Fnet = m a
Use the following info AND the info on the board to solve your Do Now! Either write this down, take a picture and re-write at home/later, or take a picture and print it out…remember, no phones on Open Notes Quizzes!
Net Force = mass x acceleration
Fnet = m a
Newton’s 2nd Law states that a Net Force applied to a mass causes a change in motion (an acceleration!)

3. Use this column for work space if needed#
Net Force
(N)
Mass
(kg)
Acceleration
(m/s2)
Use this column for work space if needed 1. 10 2 2. 20 3. 4 4. 5 5.
a = F/m
a = 10/2 5
a = F/m
a = 20/2 10
a = F/m
a = 20/4 5
F = ma
F = 2 * 5 10 1
m = F/a
m = 10/10

4. Take out your HW due today…
Rapid review
We are popcorning – pay attention!!

5. Midterm Info You are receiving your… Frequently asked question sheet
Cheat sheet

6. Jan 14th & 15th Don’t forget: Project!
Test! (there are 2 links on the test’s Genesis task that will help you prep for the test)

7. The Newton is an abbreviation!
**Remember**
Fnet = m . a
N = kg m s2
The Newton is an abbreviation!
What happens if you are solving for NEWTONS (Force)….
but are given MASS in GRAMS? (g)
Or acceleration in miles per hour per second?

9. a
a = 2 m/s2
F = 20,000 N
m = 10,000 kg
a = F / m

10. F = ma
F = 10,000 kg * 3.5 m/s2
F = N
a = F/m
**USE DA!!! 1500 g = 1.5 kg
a = 3N /1.5 kg
a = 2 m/s2

11. Do #4-5

12. FORCE & ACCELERATION are
Directly proportional
Inversely proportional
Not proportional
Not enough info to answer

13. MASS & ACCELERATION are
Directly proportional
Inversely proportional
Not proportional
Not enough info to answer

14. Do #6-7

15. Two shopping carts of equal mass are pushed by two different people
  Two shopping carts of equal mass are pushed by two different people. Cart A accelerates four times more than Cart B. Describe the magnitude or amount of force applied to Cart A compared to the Cart B.
Cart A has the same net force as the Cart B.
Cart A has 4x the net force of the Cart B
Cart A has ¼ the net force of the Cart B
Not enough info

16. Cart A experiences 4x the force of cart B!
  Two shopping carts of equal mass are pushed by two different people. Cart A accelerates four times more than Cart B. Describe the magnitude or amount of force applied to Cart A compared to the Cart B.
Cart A Cart B
Fnet = m a Fnet = m a
Force = 1 x Force = 1 x 1
Force = Force = 1
Cart A experiences 4x the force of cart B!

17.  Two shopping carts of different mass are pushed by two different people, who apply the SAME force. Cart A accelerates four times more than Cart B. Describe the mass of Cart A compared to the Cart B.
Cart A has the same mass as the Cart B.
Cart A has 4x the mass of the Cart B.
Cart A has ¼ the mass of the Cart B.
Not enough info

18. Cart 1 has ¼ the mass of cart 2!
 Two shopping carts of different mass are pushed by two different people, who apply the SAME force. Cart A accelerates four times more than Cart B. Describe the mass of Cart A compared to the Cart B.
Cart A Cart B
Fnet = m a F net = m a
1 = m x = m x 1
m = m = 1 4
Cart 1 has ¼ the mass of cart 2!

19. Newton’s Law Math Answer the True/False questions found in #8
Get your clickers ready

20. Balanced forces cause constant acceleration.
True
False
Not quite sure
Balanced forces cause ZERO acceleration. OR
Unbalanced forces cause acceleration.

21. The greater net force applied, the greater the acceleration.
True
False
Not quite sure

22. A non-zero net force (in other words, a net force MORE than 0) acting on an object causes acceleration.  
True
False
Not quite sure

23. The forces acting on an object at rest are unbalanced.
object at rest are balanced. OR
The forces acting on an object changing velocity are unbalanced.  
True
False
Not quite sure

24. Force and acceleration are inversely proportional.
Force and acceleration are directly proportional.    
True
False
Not quite sure

25. Mass and acceleration are inversely proportional.
True
False
Not quite sure

26. True False Not quite sure
  If you triple the force applied to something, you would expect 1/3 as much acceleration.
If you triple the force applied to something, you would expect 3X as much acceleration.
True
False
Not quite sure

27. If you triple the force applied to something, you would expect 3X as much acceleration.
Fnet = m a (Net Force = mass times acceleration)
1 = 1 x 1
3 = 1 x 3
NOT = 1 x 1 3

28. #9
Justin Bieber has a mass of 65 kg. After I kick him, he accelerates at a rate of 3 m/s2.
What is the net force acting on Justin?
m = 65 kg
a = 3 m/s2
F = m a
F = 195 N

29. #10a
During football practice, two linemen are pushing a coach on the sled. The combined mass of the sled and the coach is 300 kg. The sled accelerates at a rate of m/s2.
What is the net force acting on the on the sled by the linemen?
m = 300 kg
a = 0.58 m/s2
F = m a
F = 174 N

30. #10b
During football practice, two linemen are pushing a coach on the sled. The combined mass of the sled and the coach is 300 kg. The sled accelerates at a rate of m/s2.
What if another coach hopped on the sled, doubling the mass of the coach-sled system? What would be the new net force (*assuming the acceleration stayed the same)? (HINT – do you need to do the formula again, or can you think conceptually using proportions?)
If the F before was 174 N…
Force and mass are DIRECTLY proportional
If there is double the mass, the football players must now push twice as hard ( double the force) !
New force is double 174 N = 348 N

31. #11 a
A student is driving down the road when they see Miley Cyrus on a wrecking ball. They speed up, and eventually crash into Miley with a rightward force of 300 N. Miley & her wrecking ball are a combined 150 kg.
What is Miley & Wrecking Ball’s acceleration?
m = 150 kg
F = 300 N
a = F/m
a = 2 m/s2

32. #11 b
After the collision, Miley flies off the wrecking ball. Her mass is only 50 kg. The student drives into her again with a force of 300 N. What is Miley’s acceleration?
(HINT – do you need to do the formula again, or can you think conceptually using proportions?)
If the acc. before was 2 m/s2…
MASS and ACC. are INVERSELY proportional
If there is 1/3 the mass (from 150 kg to 50 kg), there is now 3x the acceleration!
Acceleration is 6 m/s2

33. a. THINK CONCEPTUALLY!! Anna Litical and Noah Formula are experimenting with the effect of mass and net force upon the acceleration of a lab cart. They determine that a net force of F causes a cart with a mass of M to accelerate at 48 cm/s2. What is the acceleration value of a cart with … a mass of M when acted upon by a net force of 2F?
24 cm/s2
48 cm/s2
72 cm/s2
96 cm/s2
None of the above

34. b. THINK CONCEPTUALLY!! Anna Litical and Noah Formula are experimenting with the effect of mass and net force upon the acceleration of a lab cart. They determine that a net force of F causes a cart with a mass of M to accelerate at 48 cm/s2. What is the acceleration value of a cart with … a mass of 2M when acted upon by a net force of F?
24 cm/s2
48 cm/s2
72 cm/s2
96 cm/s2
None of the above

35. c. THINK CONCEPTUALLY!! Anna Litical and Noah Formula are experimenting with the effect of mass and net force upon the acceleration of a lab cart. They determine that a net force of F causes a cart with a mass of M to accelerate at 48 cm/s2. What is the acceleration value of a cart with … a mass of 2M when acted upon by a net force of 2F?
24 cm/s2
48 cm/s2
72 cm/s2
96 cm/s2
None of the above

36. d. THINK CONCEPTUALLY!! Anna Litical and Noah Formula are experimenting with the effect of mass and net force upon the acceleration of a lab cart. They determine that a net force of F causes a cart with a mass of M to accelerate at 48 cm/s2. What is the acceleration value of a cart with … a mass of 4M when acted upon by a net force of 2F?
24 cm/s2
48 cm/s2
72 cm/s2
96 cm/s2
None of the above

37. e. THINK CONCEPTUALLY!! Anna Litical and Noah Formula are experimenting with the effect of mass and net force upon the acceleration of a lab cart. They determine that a net force of F causes a cart with a mass of M to accelerate at 48 cm/s2. What is the acceleration value of a cart with … a mass of 2M when acted upon by a net force of 4F?
24 cm/s2
48 cm/s2
72 cm/s2
96 cm/s2
None of the above

38. Finish the rest of the questions!
Whatever is not done is HW (EXCEPT the challenge problems!)
However, although the challenge problems aren't HW, you might see questions like that as test extra credit, so it would be a good idea to do them!