December 13 & 16

Day Prior to Test

Do Now: • Take a clicker; set aside (Take a study guide if needed)• Turn in your 4 HW questions• Write Down and Solve the following question: An applied force of 50 N is used to accelerate an object to the right, across a flat, frictional

surface. The object encounters 1 N of friction. Use the diagram to determine the normal force, the net force, the mass (in BOTH kg and g), and the acceleration of the object. (Neglect air resistance.)

HW – test next class!!!

8 N

49 N (HORIZONTAL)

1 kg = 9.8 N

So 8 N = 0.816 kg

0.816 kga = F/m

a = 60 m/s2

a = 60 m/s2 (depending how you round)

HW

• Test NEXT CLASS• Study guide is on my desk, on my website, and

on Genesis • EXTRA CREDIT IS DUE TUESDAY (tomorrow) !

Take out the HW due today! #10, 11, 29, 30!

#10 – Distinguish between force and pressure

1 2 3 4

17%

33%

0%

50%

1. pressure is a push/pull; force is surface area divided by pressure.

2. Force is a push/pull; pressure is force divided by surface area.

3. pressure is a push/pull; force is pressure divided by surface area.

4. Force is a push/pull; pressure is surface area divided by force.

#11 – which produces more pressure, a person standing up or the same person lying down ?

1 2 3 4

25%

0%0%

75%1. Laying down2. Standing up3. The same pressure4. Not quite sure

#29

• When blocking in football, why does the defending lineman attempt to push his opponent upward? What effect does this have on friction?

#30 –Why does a sharp knife cut better than a dull knife?

1 2 3 4

8%

0%

67%

25%

1. Sharp knife has MORE surface area so MORE pressure

2. Sharp knife has LESS surface area so LESS pressure

3. Sharp knife has LESS surface area so MORE pressure

4. Sharp knife has MORE surface area so LESS pressure

CHECK QUESTION – Pressure and surface area are….

1 2 3 4

33%

0%0%

67%1. Directly proportional2. Inversely proportional3. Neither4. Unsure

Do Now Complete the first 2 bullet points in your POGIL. Ms. Bones will actually do this, and you can add notes regarding what happened after.

If you did not get one already, please take a copy of the Study Guide – test NEXT CLASS

5 minutes to complete the 1st

page!

So why don’t we NOTICE earth accelerating towards the apple?

Earth Apple

m a = F = m aSAME FORCEDIFFERENT

MASSDIFFERENT

ACC.

ACC & MASSINVERSELY ~

Apple Pushes DOWN on handHand Pushes UP on apple

2 minutes to complete! (next page)

POGIL• Stopping with 15 minutes left

for a clicker review

• CHECK IN at STOP SIGNS and when you need HELP!!!

• TEST ON THIS NEXT CLASS!

POGIL # 23- 25 - clickers!

Consider 2 forces acting on person who stands still – namely, the downward pull of gravity & the upward support of the floor.23. Are the forces equal (in magnitude) & opposite (in

direction)?_____________24. Do they comprise action-reaction pair?_________

25. WHY or WHY not: (use words/pictures)

23. Consider 2 forces acting on person who stands still – namely, the downward pull of gravity & the upward support of the floor.Are the forces equal & opposite?_________

1 2 3

100%

0%0%

1. Yes2. No3. Not sure

24. Consider 2 forces acting on person who stands still – namely, the downward pull of gravity & the upward support of the floor. Do they comprise action-reaction pair?_________

1 2 3

42%

0%

58%

1. Yes2. No3. Not sure

26. Bob and Sally are the same mass. They are standing on frictionless ice. If they push each other, which person experiences the larger FORCE?

1 2 3 4

25%

0%

67%

8%

1. Bob2. Sally3. Same force4. Not quite sure

27. Bob and Sally are the same mass. They are standing on frictionless ice. If they push each other, which person experiences the larger ACCELERATION?

1 2 3 4

0% 0%

92%

8%

1. Bob2. Sally3. Same acceleration4. Not quite sure

Bob Sallyma = F = ma

28. Bob and Sally are standing on frictionless ice. Bob has GREATER MASS than Sally.If they push each other, which person experiences the larger FORCE?

1 2 3 4

50%

0%0%

50%1. Bob2. Sally3. Same force4. Not quite sure

29. Bob and Sally are standing on frictionless ice. Bob has GREATER MASS than Sally. If they push each other, which person experiences the larger ACCELERATION?

1 2 3 4

10%

0%

20%

70%

1. Bob2. Sally3. Same acceleration4. Not quite sure

Bob Sally

ma = F = ma

30. Earth and the moon are “connected” to each other by a gravitational force. If the action force is Earth pulling on the moon, what is the reaction force?

1 2 3 4 5 6

0%

9%

0%0%

82%

9%

1. Gravity pulling moon2. Sun pulling moon 3. Earth pulling moon4. Moon pulling Earth 5. Answer isn’t up here6. Not quite sure

31. Earth and the moon are “connected” to each other by a gravitational force. Which is the greater force: moon pulling on the Earth, or Earth pulling on the moon?

1 2 3 4 5

8%

33%

8%

0%

50%

1. Moon pulling Earth 2. Earth pulling moon3. They are the same

force4. Answer isn’t up here5. Not quite sure

Earth Moon

ma = F = ma