CP Physics

We finish the marble lab if necessary, and look at the video of a football being thrown through the air. The main lesson is: sideways motion is constant speed, while up and down motion is affected by gravity and thus gets faster and slower.

Please look at the review questions in Chapter 3 for next class. We will continue our "stand and deliver" approach for the review questions.

The previously assigned homework is due.

We are going to set up the equipment necessary to determine the speed a marble shoots off of a table. Then using this information and the height of a table, we are going to predict the landing site of a marble. Placing a cup there, we will shoot the marble off the table into the cup...if the marble goes in, you pass. If it doesn't...you don't.

Today we assigned the entire batch of "Plug and chug" problems from Chapter 2 (there are 8) and in addition Think and Explain problems 5,6, and 8 -- I am not able to post these messages from school, so those problem numbers may be wrong. If anyone reads this and can verify I wrote it down right, please drop a note to astronomyteacher@mac.com.

In addition, I suggested students wishing to get ahead should look at Chapter 3, which has to do with vectors and projectile motion. We are going to attempt to theoretically predict the landing site of a marble rolling off a table in class next week.

In class today we did "stand and deliver" for the review questions assigned in class. This took most of the period.

Some things we went over included how to set up the mathematical solutions to physics problems, the conceptual difference between velocity and acceleration and the fact that acceleration can be negative.

As homework, students were assigned the task of measuring their reaction time by dropping a ruler 10 times, catching it, and using the distance it fell in the reaction time equation to solve the problem. Most should get an answer around 0.15 seconds or so.

Acceleration is defined as the rate of change of velocity.

You can accelerate through changing your speed or changing your direction or both. This was demonstrated in class using the "water cup" accelerometer model.

Acceleration graphs were explained as the slope of the velocity graph in much the same way the velocity graph is the slope of the distance vs. time graph.

We assigned all the review questions at the end of Chapter 2.

We spend the day in the planetarium because the seniors were out.

Homework is due. This includes the worksheet as well as the graph drawn on the board which we will discuss in class.

Velocity vs. time graphs on the motion sensor.

Families of graphs describing different kinds of motion on both d vs. t and v vs. t graphs.

Standing still, walking towards, walking away, accelerating away and decelerating away as examples.

Interpreting curved v vs. t graphs. Definition of acceleration in terms of changing velocity.

Connecting slopes to these graphs. The slope of d vs. t is v; the slope of v vs. t is a.

Calculating simple problems in acceleration.

A series of demonstrations with the Vernier sonar sensor to nail down some basic concepts of kinematics.
Books distributed, if we have them... we do! But they have to be indexed by the library first.

The demonstrations will be accompanied by definitions of
position
displacement
speed
velocity, instantaneous and average

d vs. t graphs and
v vs. t graphs will be shown.

a short worksheet of problems was given for homework.

Homework:

Sample speed-distance-time problems

1. A car leaves Antioch driving 50 mph west. How long will it take to travel 300 miles? yes, you can do this in your head--but write it out in the format shown in class.




2. A car leaves a stop light starting from rest, and steadily picks up speed until it reaches 40 mph after 20 seconds.
a) what was its average speed?
b) what was its instantaneous speed
i) at first?
ii) at 10 seconds?
iii) at 20 seconds?
c) how far did it travel? (don’t forget to attend to units!)


3. An airplane flies from Oakland to LA in an hour. Assume the distance is 400 miles.
a) What is the airplane’s average speed during the flight?
b) What is the airplane’s instantaneous speed during the flight?
c) If we include arriving at the airport, security, getting luggage, etc., the trip takes 4 hours, including the flight itself. What is the traveler’s average speed for the entire trip? Is this faster or slower than just driving a car at the speed limit?

GREAAT Science review and discussion
Formula sheet
Analysis of some of our physics equations

Units of measurement
Differences in equations from chemistry, physics, and algebra class
subscripts, conventions, etc.
Brief overview of vectors
Displacement
Change in position
Average vs. Instantaneous velocity
D vs. T graphs
Vernier sensor probes
The definition of acceleration (rate of change of velocity)

First day lesson plans:

Attendance
Class rules
Contact information
Textbook and suggested supply list
Scientific calculator
3-ring binder for notes and handouts
colored pencils

Your first homework assignment: read GREEAT Science.
GREEAT Science

We will begin the class with some definitions of kinematics.