Describing Motion

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


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


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.


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.


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.


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).


Just like the previous graph, this graph shows an object moving with constant velocity.


The curve, in the graph, shows that the object’s velocity is changing as time passes.

This is acceleration.


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.


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


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.


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



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?


Check Your AnswerA 56 kg cart is accelerating at 15 m/s2.

Calculate the force exerted on the cart?


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.


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.


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.


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.


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

Documents

Describing Motion