Welcome Back to Physics

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Welcome Back to Physics
My Dog
Ajax
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Your 5 minutes starts now
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Objective I can distinguish between scalar and
vector quantities, and calculate displacement.
Bellringer Question A scientist follows the
path below. How far has he walked? How far is he
from where he started?
Your 5 minutes starts now!
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Objective I can distinguish between scalar and
vector quantities, and calculate displacement.
Bellringer Question A scientist follows the
path below. How far has he walked? How far is he
from where he started?
4 minutes left and counting
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Objective I can distinguish between scalar and
vector quantities, and calculate displacement.
Bellringer Question A scientist follows the
path below. How far has he walked? How far is he
from where he started?
3 minutes left and counting
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Objective I can distinguish between scalar and
vector quantities, and calculate displacement.
Bellringer Question A scientist follows the
path below. How far has he walked? How far is he
from where he started?
2 minutes left and counting
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Wrap up your answer
And get ready to start the lesson
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Time is UP!
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Agenda

• Bellringer
• Announcements
• Guided Notes Vectors vs. Scalars, Displacement
  vs. Distance
• Independent work
• Homework
• What you dont finish in class on worksheet
• Study for QUIZ 1 on Friday

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Vectors and Scalars

• Magnitude size. In scalar and vector quantities,
  its the number.
• 2 shoes the magnitude is 2
• 178 lbs the magnitude is 178
• 8.6 miles south the magnitude is 8.6

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Vectors and Scalars

• Scalar Quantity a quantity with JUST a magnitude
• EXAMPLES
• Seven birds
• 15 pounds
• 8 meters
• 8 seconds

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Vectors and Scalars

• Vector Quantity a quantity with a magnitude AND
  a direction
• EXAMPLES
• 6 meters north
• 3 steps left
• 1 mile up
• 453 inches down

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Vectors and Scalars

• Is it a vector or a scalar?
• I went 2 blocks east to the store.
• There are 6 apples in the fridge.
• I have a math class 1 floor up from this room.
• I walked 47 meters
• I walked 47 meters north

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Vectors and Scalars

• Is it a vector or a scalar?
• I went 2 blocks east to the store.
• There are 6 apples in the fridge.
• I have a math class 1 floor up from this room.
• I walked 47 meters
• I walked 47 meters north

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Distance and Displacement

• Might be tempted to think they are the same
  thing, BUT THEY ARE NOT.
• Foundation of many of the other quantities we use
  in physics--and especially this unit

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Distance and Displacement

• Distance a SCALAR QUANTITY that means how much
  ground an object covered during its motion.
• EXAMPLE If I walk to the far end of the
  classroom and back, I walked a non-zero distance.

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Distance and Displacement

• Displacement a VECTOR QUANTITY that means how
  far an object is from where it started.
• EXAMPLE If I walk to the far end of the
  classroom and back I have zero displacement.

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Distance and Displacement

• Think football.

Which line shows Jay Cutlers displacement? Which
shows his distance?
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Distance and Displacement

• How to find displacement
• 1. Find the vectors in the problem
• 2. Draw a picture
• 3. Find how far the object is from where it
  started

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Distance and Displacement

• How to find distance
• 1. Find the magnitudes in the problem
• 2. Draw a picture
• 3. Add up all the magnitudes to see how much
  ground the object covered.

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Distance and Displacement

• Fatima is pacing back and forth in front of
  Harlan, waiting for the doors to open. She walks
  north 50 m, then south 60 m, then north 70 m.
• Displacement
• Find the vectors
• Draw a picture
• How far from where she started?

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Distance and Displacement

• Fatima is pacing back and forth in front of
  Harlan, waiting for the doors to open. she walks
  north 50 m, then south 60 m, then north 70 m.
• Displacement
• Find the vectors
• Draw a picture
• How far from where she started?

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Distance and Displacement

• Displacement
• Find the vectors
• Draw a picture
• How far from where she started?

70 m
60 m
50 m
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Distance and Displacement

• Displacement
• Find the vectors
• Draw a picture
• How far from where she started?

70 m
After she walks 50 m North, displacement is 50 m
North
60 m
After she walks 60 m South, displacement is 10 m
South
After she walks 70 m North, displacement is 60 m
South
50 m
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Distance and Displacement

• Distance
• Find the magnitudes
• Draw a picture
• Add the magnitudes how much ground was covered?

70 m
After she walks 50 m, distance is 50 m
60 m
After she walks 60 m more, distance is 110 m
After she walks 70 m more, distance is 180 m
50 m
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Distance and Displacement

• Xxavier walks 8 m west, then 4 m east, then 2 m
  west. What distance did he walk? What is his
  displacement?

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Distance and Displacement

• Bellringer Question
• A scientist follows the path below. How far has
  he walked? How far is he from where he started?

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Independent Practice

• Complete Worksheet
• What you dont finish in class you will finish as
  homework, to be turned in tomorrow for a grade
• Limited talking is fine, but focus is on the work
• Well stop with 6 min left in class for exit
  ticket