Do Now Chart on page 2 of your notes!. Net Force = mass x acceleration F net = m a Newton’s 2 nd Law states that a Net Force applied to a mass causes.

Do Now

Chart on page 2 of your notes!

Net Force = mass x accelerationFnet = m aNewton’s 2nd Law states that a Net

Force applied to a mass causes a change in motion (an acceleration!)

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(N)

Mass (kg)

Acceleration(m/s2)

Use this column for work space if needed

1. 10 2

2. 20 2

3. 20 4

4. 2 5

5. 10 10

Take out your HW due today…

• Rapid review• We are popcorning – pay attention!!

Midterm Info

• You are receiving your…– Frequently asked question sheet– Cheat sheet

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)

• What happens if you are solving for NEWTONS (Force)….– but are given MASS in GRAMS? (g)– Or acceleration in miles per hour per

second?

**Remember**

Fnet = m . aN = kg m s2

The Newton is an abbreviation!

Do #4-5

FORCE & ACCELERATION are

A. Directly proportional

B. Inversely proportional

C. Not proportionalD. Not enough info to

answer

Directl

y proporti

onal

Inverse

ly pro

portional

Not pro

portional

Not enough in

fo to

answ

er

0% 0%0%0%

MASS & ACCELERATION are

A. Directly proportional

B. Inversely proportional

C. Not proportionalD. Not enough info to

answer

Directl

y proporti

onal

Inverse

ly pro

portional

Not pro

portional

Not enough in

fo to

answ

er

0% 0%0%0%

Do #6-7

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.

1. Cart A has the same net force as the Cart B.

2. Cart A has 4x the net force of the Cart B

3. Cart A has ¼ the net force of the Cart B

4. Not enough info

Cart A has t

he same net f

...

Cart A has 4

x the net f

orc...

Cart A has ¼

the net f

orc...

Not enough in

fo

0% 0%0%0%

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 4 Force = 1 x 1

Force = 4 Force = 1

Cart A experiences 4x the force of cart B!

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.

1. Cart A has the same mass as the Cart B.

2. Cart A has 4x the mass of the Cart B.

3. Cart A has ¼ the mass of the Cart B.

4. Not enough infoCart

A has the sa

me mass.

..

Cart A has 4

x the m

ass of...

Cart A has ¼

the m

ass of t

..

Not enough in

fo

0% 0%0%0%

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 4 1= m x 1

m = 1 m = 1 4Cart 1 has ¼ the mass of cart 2!

Newton’s Law Math

• Answer the True/False questions found in #8• Get your clickers ready

Balanced forces cause constant acceleration.

1. True2. False 3. Not quite sure

Balanced forces cause ZERO acceleration.

OR Unbalanced forces cause acceleration. Tru

e Fa

lse

Not quite

sure

0% 0%0%

The greater net force applied, the greater the acceleration.

1. True2. False 3. Not quite sure

True

False

Not quite

sure

0% 0%0%

A non-zero net force (in other words, a net force MORE than 0) acting on an object causes

acceleration.

1. True2. False 3. Not quite sure

True

False

Not quite

sure

0% 0%0%

The forces acting on an object at rest are unbalanced.

1. True2. False 3. Not quite sure

The forces acting on an object at rest are balanced.

ORThe forces acting on an object changing velocity are unbalanced.

True

False

Not quite

sure

0% 0%0%

Force and acceleration are inversely proportional.

1. True2. False 3. Not quite sure

Force and acceleration are directly proportional.

True

False

Not quite

sure

0% 0%0%

Mass and acceleration are inversely proportional.

1. True2. False 3. Not quite sure

True

False

Not quite

sure

0% 0%0%

If you triple the force applied to something, you would expect

1/3 as much acceleration.

1. True2. False 3. Not quite sure

If you triple the force applied to something, you would expect 3X as much acceleration.

True

False

Not quite

sure

0% 0%0%

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 3 = 1 x 1 3

#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 kga = 3 m/s2

F = m aF = 195 N

#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 0.580 m/s2. – What is the net force acting on the on the sled by the

linemen?

m = 300 kga = 0.58 m/s2

F = m aF = 174 N

#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 0.580 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 proportionalIf 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

#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 kgF = 300 Na = F/ma = 2 m/s2

#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 proportionalIf there is 1/3 the mass (from 150 kg to 50 kg), there

is now 3x the acceleration!Acceleration is 6 m/s2

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?

A. 24 cm/s2

B. 48 cm/s2

C. 72 cm/s2

D. 96 cm/s2

E. None of the above

0% 0% 0%0%0%

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?

A. 24 cm/s2

B. 48 cm/s2

C. 72 cm/s2

D. 96 cm/s2

E. None of the above

0% 0% 0%0%0%

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?

A. 24 cm/s2

B. 48 cm/s2

C. 72 cm/s2

D. 96 cm/s2

E. None of the above

0% 0% 0%0%0%

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?

A. 24 cm/s2

B. 48 cm/s2

C. 72 cm/s2

D. 96 cm/s2

E. None of the above

0% 0% 0%0%0%

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?

A. 24 cm/s2

B. 48 cm/s2

C. 72 cm/s2

D. 96 cm/s2

E. None of the above

0% 0% 0%0%0%

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!