How do you know if something is in motion? Motion – changing position in space.
10/1/14 Changing motion
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10/1/14 Changing motion Science video : Run or Slide Sign up for Egg drop assignment Revisit motion pretest Review fan cart graphs Define acceleration Practice acceleration concepts Name that motion activity Homework: Worksheets Describing Motion with Diagrams , Describing Motion numerically , read associated sections.
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10/1/14 Changing motion. Science video : Run or Slide Sign up for Egg drop assignment Revisit motion pretest Review fan cart graphs Define acceleration Practice acceleration concepts Name that motion activity - PowerPoint PPT Presentation
Transcript of 10/1/14 Changing motion
10/1/14 Changing motionScience video: Run or SlideSign up for Egg drop assignmentRevisit motion pretestReview fan cart graphsDefine accelerationPractice acceleration conceptsName that motion activityHomework: Worksheets
Describing Motion with Diagrams, Describing Motion numerically, read associated sections.
Learning objectivesApply the definition of
acceleration to solve for an unknown
Interpret the slope of a velocity vs time graph
Give a verbal description of the motion of a moving object
Revisit Motion pretestDoes today’s activity
help us answer any of the Motion pretest items?
How do we know if there is acceleration?◦ When the velocity
does not change.◦ Item 6 on the pretest
asks about this.Let’s look at
yesterday’s graphs
Sample Velocity vs. time graph
The line equation isy = mx + b
What are y, x, m, b?
Here y is velocity, x is time, m describes the rate of speeding up, and b is initial velocity
0 0.5 1 1.5 2 2.5 3 3.50
2
4
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10
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f(x) = NaN x + NaNR² = 0 How velocity changes dur-
ing the trip
Time (s)
Velo
cit
y (
cm
/s)
Sample Position vs. time graph
What does each parameter represent here?
Look at similarities with the previous equation.
Here y is position, x is time, 8.1279 is 1/2a, 22.288 is initial velocity and 0.8107 is initial position.
0 0.5 1 1.5 2 2.5 3 3.50
20
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60
80
100
120
140
160
f(x) = 8.1279072707048 x² + 22.287649155627 x + 0.8106671554252R² = 0.999929612637343
Acceleration Graphing (Position)
Time (s)
Posi
tion (
cm
)
AccelerationThe slope of a position vs. time graph is the velocity.If the velocity is changing, the slope at each point
represents the velocity at that point.The slope of a velocity vs. time graph is the
acceleration.Definition of acceleration:Acceleration = change in velocity/change in time
a=∆v/ ∆t (= rise of v vs t graph/run of v vs t graph)The more the velocity changes for a set time
interval, the greater the slope and the greater the acceleration.
Acceleration can be positive or negativeReview acceleration homework
Name That Motion activity
Go to http://www.physicsclassroom.com/shwave/namethat.cfm or http://goo.gl/yhw95
Work in your table groups. Just enter one name.
View each motion. Copy down the pattern of dots for each motion.
Type the number of the description on the worksheet that matches the motion.
Staple the worksheet to your notebook.
Motion graphs for the activity
