describing motion
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Describing Motion
Warm Up
Test Review
Test Review
Test 3 = Questions 1,2,11,12,13,14,15,16› 8 Total› 12.5 points a piece
Test 4 = All the other question › 17 Total› 5.8 points a piece
Speed, Velocity, Acceleration
“Find Someone Who” can tell you what speed, velocity, and acceleration are. › You must locate three different peers to tell
you what they think these terms mean and record the answers in the “What we think” row of the document.
› You are expected to answer as well as ask.› It’s OK to be wrong but your must have and
answer › The student who answers needs to sign
his/her name next to their answer. 2 minute time limit per word
Speed, Velocity, Acceleration
Now list an “A” for agree or a “D” for disagree next to the definitions
Turn to your shoulder partner and explain why they agree or disagree with the definitions.› You have 2 ½ minutes› GO
Speed, Velocity, Acceleration
Update your handouts by recording the scientific definitions of speed, velocity, and acceleration in the “What We Know” row of their handouts.
The PowerPoint will instruct you to record examples as they complete their notes on the handout.
Speed The distance an object travels in a
certain amount of time.
› Average speed – Total distance divided by total time
› Constant speed - Speed that does not change
On your paper, describe an example of an object at a constant speed.
What is the formula for calculating speed?
Speed equals distance divided by time.
Let’s Practice Calculating Speed
A football field is about 100 meters long. If it takes a person 20 seconds to run its length, how fast was the football player running?
On the side of your paper, calculate this problem. Make sure you show all work!
Check Your Work
A football field is about 100 meters long. If it takes a person 20 seconds to run its length, how fast was the football player running?
› Speed = Distance ÷ Time
› Speed = 100 m ÷ 20 s› Speed = 5m/s
Remember to label
the UNITS!!
Velocity
An object’s speed and direction at a given time› The wind is blowing 65 km/hr from the
North.
On your paper, describe an example of velocity.
Acceleration A change in the direction or speed
(velocity) of an object over time – which may be:› A change in speed
Starting Stopping Speeding up (positive acceleration) Slowing down (negative acceleration)
› A change in direction Acceleration is caused by unbalanced forces. On your paper, describe an example of an
object accelerating.
Speed, Velocity, Acceleration
How does your “What We Think” section compare to your “What We Know” section?
Does anyone notice any differences in the meaning of the three terms? Explain.› Speed is distance/time, velocity is
speed with a direction, and acceleration is a change in speed and/or direction.
Speed, Velocity, Acceleration
The terms we have noted are extremely important in our upcoming unit of study. Be prepared to refer back to them often.
Highlight, circle, or underline the key points
Warm Up
Video
http://www.youtube.com/watch?v=DRb5PSxJerM
Calculating and Graphing Speed
Title the next blank page Calculating and Graphing Speed
You are going to draw 5 easy graph and interpret the speed
Interpret the Graph Below:
The graph shows an object which is not moving (at rest).
The distance stays the same as time goes by because it is not moving.
Interpret the Graph Below:
The graph showsthat the objects distance increases as time passes.The object is moving and so it has velocity.
The straight line shows it is a constant (not changing).
Interpret the Graph Below:
Just like the previous graph, this graph shows an object moving with constant velocity.
Interpret the Graph Below:
The curve, in the graph, shows that the object’s velocity is changing as time passes.
This is acceleration.
Interpret the Graph Below:
In the first part of the graph, the object is moving with constant velocity.
In the second part of the graph, the object is at rest (not moving).
In the third part, the object is again moving with constant velocity.
Calculating and Graphing Speed
LAB instructions Everyone is always recording Group Roles (you will rotate jobs)
› Roller› Timer 1› Timer 2› Timer 3› Director
Says Start and Stop Is in Charge
Warm Up
Calculating and Graphing Speed
Continue the lab Group Roles (you will rotate jobs)
› Roller› Timer 1› Timer 2› Timer 3› Director
When you are finished sit back at your desk and complete the graph and the questions› Work together› Turn in when you are finished› Use COLOR on the graph
Warm Up
Directions: 1. Read the following scenario. 2. Calculate the average speed. 3. Briefly describe all points of acceleration and
explain.
A female cheetah left her cubs to hunt for food. She sprinted 30 m away from her den in two seconds. Next, she turned around and traveled 10 meters back toward her den in three seconds. She suddenly stopped and listened intently for two seconds. Then, she traveled 40 meters away from her den in four seconds.
Card Sort
With your face partner, sort the cards into 3 groups
Story Graphs
With your groups, write a 10 sentence story using 2 of the four graphs.
Your story must include:› The average speed› Acceleration› Main Character› Plot› Be creative› 10 pictures› Use two iPad› Be prepared to share
Warm Up
Write Tug of War on your warm up
Open Tug of War Handout in eBackpack
Warm Up
Change the Motion of an Object
Open Change the Motion of an Object in ebackpack› You will answer the questions ON THE
FIRST PAGE as you complete the lab
Using the object that I give you make it accelerate AT YOUR DESK!!!!!!!!!!!
Make it stop, start, speed up, slow down, and change direction
Volunteer to Share
Pass out the laminated paper
Change the Motion of an Object
With your should partner look at the handout.
Describe the motion of the object. › Such as: left, right, up, down
Then explain to your partner why your think the object will move in a certain direction. › Use words like: balanced, unbalanced,
force, motion and acceleration
Notes
Volunteer to share
Now you are going to start filling out the rest of the paper from ebackpack
Copy what is in yellow and include a quick picture
Motion A change in the position of an object
Caused by force (a push or pull)
Force
A push or pull on an object Measured in units called newtons (N) Measured with a spring scale Forces act in pairs
Types of Force: (pick two)› gravity› electric› magnetic› friction› centripetal
Balanced Forces When all the forces acting on an object are
equal (net force is zero)
Balanced forces do not cause a change in motion.
Balanced forces can change the physical properties of an object without changing its motion.
In your notes, describe an example of a balanced force.
How Can Balanced Forces Affect Objects?
Cause the shape of an object to change without changing its motion
Cause an object at rest to stay at rest or an object in motion to stay in motion (inertia)
Cause an object moving at a constant speed to continue at a constant speed
In your notes, describe an example of a balanced force affecting an object.
Inertia
1. An object at rest will remain at rest until acted upon by an unbalanced force.
2. An object in motion will remain in motion until acted upon by an unbalanced force.
3. When all forces acting on an object are equal (balanced)
Unbalanced Forces
When all the forces acting on an object are not equal
The forces can be in the same direction or in opposite directions.
Unbalanced forces cause a change in motion.
In your notes, describe an example of an unbalanced force.
How Can Unbalanced Forces Affect Objects?
Acceleration is caused by unbalanced forces:› slow down› speed up› stop › start › change direction› change shape
In your notes, describe an example of an unbalanced force affecting an object.
Net Force The total of all forces acting on an
object:
› Forces in the same direction are added. The object will move in the direction of
the force.
› Forces in opposite directions are subtracted. An object will move in the direction of
the greater force.
Balanced forces do not cause a change in motion.
Warm Up
Open your notes from yesterday and prepare to finish taking notes
Copy what is in YELLOW and include a quick picture
Calculating Net Force 1
30 N 10 N
A child was playing with a jack in the box. The lid pushed down with 10 N of force, while the spring pushed up with 30 N of force. What is the net force applied by the spring?
In your notes, calculate the net force and show all of your work.
http://commons.wikimedia.org/wiki/File:Jack-in-the-box.jpg
Check Your Answer
30 N 10 N
A child was playing with a jack in the box. The lid pushed down with 10 N of force, while the spring pushed up with 30 N of force. What is the net force applied by the spring?
30 N to the right + 10 N to the right = 40 N to the right
http://commons.wikimedia.org/wiki/File:Jack-in-the-box.jpg
Calculating Net Force 2
30 N 50 N
Two competitors are playing tug of war. What is the net force? Which direction will the rope move?
In your note, calculate the net force and show all of your work.
Tug of War Game
Check Your Answer
30 N 50 N
Two competitors are playing tug of war. What is the net force? Which direction will the rope move?
50 N to the right – 30 N to the left = 20 N to the right
Tug of War Game
Force Arrows
Open the Data Sheet in ebackpack
You are completing the first half of the first page
You have 5 minutes to rotate around the room and find three DIFFERENT partners. You will combine arrows. You decide which direction you want them to turn. Fill in the chart
Mass and Weight Mass is the amount of stuff (matter) in an object.
› The mass of an object will remain the same anywhere in the universe.
› Mass is measured in grams or kilograms.
Mass and Weight Weight is the mass (kg) of an object multiplied by the
acceleration of gravity (9.8 m/s2).› The weight of an object depends on the gravitational pull of the
location in the universe.› The gravitational pull on the Moon is only 1/6 of Earth’s
gravitational pull.› Weight is measured in newtons (N).
Mass and Weight Example: F=ma
A person with a mass of 25 kg x 9.8 m/s2
gravitational acceleration is equal to 245 N of weight force.
F= 25 kg x 9.8 m/s2
F = 245 N
The person exerts 245 N of force on the ground.
If the person went to the Moon, they would only weigh 1/6
of 245 N.
Force Force (N) = mass (kg) x
acceleration (m/s2)
F ÷
m x a
Force Acceleration (m/s2) = force (N) ÷
mass (kg)
F ÷
m x a
Force Mass (kg) = force (N) ÷ acceleration
(m/s2)
F ÷
m x a
PracticeThe acceleration of a sprinter is 10 m/s2. The
force exerted on the starting blocks is 650 N. What is the mass of the sprinter?
Force = Mass = Acceleration =
Check Your AnswerThe acceleration of a sprinter is 10 m/s2. The force
exerted on the starting blocks is 650 N. What is the mass
of the sprinter?
Force = 650 N Mass = 65 kg Acceleration = 10 m/s2
Mass = force ÷ acceleration
Mass = 650 ÷ 10 Mass = 65
PracticeA 56 kg cart is accelerating at 15 m/s2.
Calculate the force exerted on the cart?
Force = Mass = Acceleration =
Check Your AnswerA 56 kg cart is accelerating at 15 m/s2.
Calculate the force exerted on the cart?
Force = 840 N Mass = 56 kg Acceleration = 15 m/s2
Force (N) = mass (kg) x acceleration (m/s2)
Force = 56 x 15 Force = 840
PracticeA boat is pulling a 54 kg wake boarder. She
accelerates at 2 m/s2. Calculate the force that is causing the acceleration.
Force = Mass = Acceleration =
Check Your AnswerA boat is pulling a 54 kg wake boarder. The
force the boat is exerting on her is 108 N. Calculate her acceleration.
Force = 108 N Mass = 54 kg Acceleration = 2 m/s2
Acceleration = force ÷ mass Acceleration = 108 ÷ 54 Acceleration = 2
Force Mass and Acceleration Cards
Open the Data Sheet again
You are completing the second half of the first page
You have 5 minutes to rotate around the room and find three DIFFERENT groups of three. › Each group must have a Force, Mass,
and Acceleration card
Force Mass and Acceleration Cards
The remaining two pages are homework due tomorrow.
You may spend the rest of the period working on them
Warm UpA boat is pulling a 54 kg wake boarder. She
accelerates at 2 m/s2. Calculate the force that is causing the acceleration.
Force = Mass = Acceleration =
Review
F ÷
m x a
Review
The total of all forces acting on an object:
› Forces in the same direction are added. The object will move in the direction of
the force.
› Forces in opposite directions are subtracted. An object will move in the direction of
the greater force.
Review
Unbalanced forces cause a change in motion.
Balanced forces do not cause a change in motion.
Warm Up
What is Force measured in?› Newtons (N)
What is acceleration measured in?› D/T› Such as:
m/s, miles/hour, ect
What is mass measured in?› Weight› Such as:
Lbs, kg, ect
Effects of Unbalanced Forces Lab
Remember Your Lab Safety Rules
You must show an understanding of speed, velocity, and acceleration.
This is a Test Grade!
Call me over when you get to the graphing part
Warm Up
Turn in your Effects of Unbalanced Forces Experiment right now even if you are not finished
Write test on your warm up log
Turn in your warm up log
Study your notes and labs for the next ten minutes
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