Kinematics

Study of How Things Move

What am I doing?

How do you know?

Frame of ReferenceAll motion is relative. What does that mean?

Car Commercial

Describing Motion

What can we measure?Science is about Quantitative Descriptions

What relationship are we trying to determine?

From the useful measurements, what is our objective?

To find a relationship between what and what?

What should we do with the data?

So we are making measurements, but what do we do

with them?

• Table? What do we put in the table? So we need

signs for those things, right?o t=time and x=position (y if vertical)

• When our table is full of data, then what?o Graph it! We need axes. Which variable goes on which axis?

o Time is independent (x-axis)

o Position depends on the time (y-axis)

• Alright! Let’s do this! Wait, what are we doing?

The Breadcrumb MethodHow we collect data

Do NOT write down this data. It’s not yours!

• Mark Origin

• Mark Starting Point (different from origin, positive or

negative)

• Sync the stopwatch and the starting of the buggy

(figure it out)

• Use tape tick marks to mark the position of the back

of the buggy every 2 seconds.

Jobs• Meter Stick – grab a meter stick for the group

• Stopwatch – grab a stopwatch for the group

• Taper – grab a role of tape for the group

• Data Collector – take data in a table for the group

WhiteboardsWith your group, sketch your graph on a whiteboard.

Don’t use a meter stick or make tick marks, make a

general sketch.

Write the equation of line of best fit near your sketch.

When you’re finished, gather around for a … wait for

it… board meeting!

Get it?

Board MeetingClass discussion. Sit so everyone can see the boards.

I’ll help lead the discussion this time, but eventually

you won’t need me as much.

What’s the same about everyone’s boards?

What’s different?

The Take HomeSlope of the position-vs-time graph is Velocity.

Positive or Negative tells us direction.

Steepness tells us magnitude.

Constant Velocity Particle Model

Look at all the pieces of our model:

• Verbal piece from our observations

• “Breadcrumb” motion map on the floor/table

• Table of data points

• Position-vs-time graph features

What’s left in the CVPM?

• Velocity-vs-time graphs

The Test!

Homework“Motion Maps” Reading

It’s 1 page, front and back. There’s a lot of pictures.

Deal with it!

Put ?’s next to words you don’t know. Make notes in

the margin. Come ready to talk about motion maps!

Day 2 – Constant VelocitySched:

• Starter

• Recap

• Wkst 1

Starter: If you’re driving on the highway at 70mp…

A. How far down the road will you be in 3.5 hours?

B. How long will it take you to go on a 300 mile trip?

And the answers are…• Starter: If you’re driving on

the highway at 70mp…

• A. How far down the road

will you be in 3.5 hours?

o 245 miles

• B. How long will it take you

to go on a 300 mile trip?

oAbout 4.3 hours

Objective:

TLWBT read graphs,

table, motion maps

and written

descriptions and

express motion in

graphs, table, motion

maps and written

descriptions

Let’s RecapFrame of Reference

• In order to describe motion, you have to pick a “frame of reference”

o Frame of reference is always decided by the

observer

o In physics we often use a coordinate axis to

denote our frame of reference.

Frame of Reference

-x

-Y

x

Y

This is a familiar coordinate axis, but in physics it has a slightly different meaning.

Frame of Reference

• In this frame of reference, up is positive,

right is positive

• Down in negative, as is left

• Hence in physics a negative has no

value, it merely denotes direction

• This is necessary because direction has a

special distinction in physics; it separates

vector quantities from scalar quantities

Vector vs. Scalar

• A Scalar Quantity is one that has only magnitude – distance is a scalar

o Example: If you travel 500 miles that is a distance

• A Vector Quantity is one that has magnitude and direction – displacement is a vector

o Example: If you travel 500 miles North this is displacement

Distance and Displacement

• Distance is a scalar. Think about a pedometer or an odometer.

o Example: If you travel 500 miles that is a distance

• Displacement is a vector. Displacement is the shortest path from start to finish. “As the crow flies.”

o Example: If you travel 500 miles North this is displacement

Distance and Displacement

Let’s say you walk 5m to the right, 3 meters up, another 5 meters to the right, and finally 4 meters up.

Your distance is the total meters you walked: 17m.

Your displacement is simply the difference between finish and start: ~12m.

5m

5m

3m

4m~12m

Speed and Velocity

If you divide distance by time you get average

speed (scalar)

• Example: S = D/t = 500 miles/2 hours =250 mph

If you divide displacement by time you get

average velocity (vector)

• Example: Vavg = Δx/Δt = 500 miles North/2 hours

= 250 mph North

Motion Maps

Cooperative Learning

Whiteboard Worksheet 1I will present a problem from the worksheet.

In groups, you will talk through and solve the problem

on the whiteboard. Really work through it and make

sure each group member really understands.

We will talk about answers and misconceptions. Then,

as a class we can write correct answers and ideas on

our worksheets.

Day 3 – Constant Velocity

Sched:

• Starter

• Check Wkst1

• V vs T graphs

• Wkst2

TLWBAT interpret and draw V vs. T

Graphs.

Starter: How far does your

car travel when you one-

handedly text “LOL” to your

friends.

Velocity vs. Time Graphs

Let’s make some guesses!

Whiteboard Worksheet2

In groups, you will talk through and solve the problem

on the whiteboard. Really work through it and make

sure each group member really understands.

We will talk about answers and misconceptions. Then,

as a class we can write correct answers and ideas on

our worksheets.

Units of Area on V vs. T Graphs

Day 4 – Constant Velocity

Sched:

• Starter

• Motion

Detector Lab

• Quiz?

TLWBAT reenact physically any motion given in a prompt.

Starter: Find the total distance

covered and total displacement.

Buggy Lab Part 2Battle Royale

2m

Where will they hit each other?