9/19 lib dub! pick a seat pick up a ruler and graph paper the seat you seat in on monday will be...

9/19 Lib Dub!Pick a seatPick up a ruler and graph paper

The seat you seat in on Monday will be your new seat. Anyone sitting towards back of class will be moved forward.

9/22 We will be working on graphs this weekPick a seat Anyone sitting towards back of class will be moved forward.

Pick up disp v time graph WS II

Tests are graded. Corrections will be available Mon –Thu am or pm. Test retakes Mon –Thu pm only

Corrections: Show all work on your own paper. Title Motion Test Corrections, include name & period. Place corrections paper clipped to your test and place in white period drawer. When you have completed them turn them into the balck basket on top on the white drawers. Tests are not to leave my room

9/22 We will be working trig

Test Tuesday

Pick a seat

The graphs…

Game

To begin, consider a car moving with a constant, rightward (+) velocity of 10 m/s

What would a Position vs Time graph of this motion, look like?

The slope of the line on a position-time graph is the velocity of the object.

And the slope is…

Example A car moves in a straight line and its odometer readings are plotted against time.a. Find the speed of the car at points A and B.

t

x

08

04

= 0.5 m/s

A

B

Same for A and B

b. What is the car's average speed?

= 0.5 m/s v

c. What is its acceleration?

a = 0 m/s2

Compare contrast

No motion, constant velocity, and acceleration on DvT graph

Let’s compare the motions shown here

Compare the velocity of the red line to the…

Green line Blue line

Black line

Orange line

And this trip shows?

Now consider a car moving with a changing, rightward(+) velocity that is, a car that is moving rightward and speeding up or accelerating.                                                                    

And the graph’s shape is?

What if the shape of the graph is a curve?

A curve shows a changing velocity or acceleration.

Slope of a curve?

(3.0s, 18m) and (3.5s, 23m)

V1 = (23m -18m) = 10m/s (3.5s -3.0 s)

(1.4s, 6m) and (2.0s, 9m) V2= (9m - 6m) = 5 m/s (2.0s - 1.4s)

The instantaneous velocity of an object at a certain time is the slope of the position (displacement) versus time graph at that time. It can be positive, negative, or zero.

What shows the instantaneous speed in the car?

Compare contrast

No motion, constant velocity, and acceleration on VvT graph

The graphs…

Homework: Graphing Motion #1

NOT!! Be ready next class for 2 wkshts instead of one.

In this lab you will measure your motion with a sonic motion detector. The motion detector emits sound waves and then detects them after they have reflected off of some object (such as you or your lab partners!). A computer then records distance from the detector to the object as a function of time. You will practice making and interpreting position-time graphs.