# GAVS Physics AB Course Resources

## Instructor Information

Emily Kroutil

Phone: 470-238-8663 (voicemail)

The resources in this newsletter are in addition to those found in MODULE 2: One Dimensional Kinematics of your course content. You should first go through the content and complete the quizzes and activities. These resources are to supplement your understanding of the concepts. Please contact me if you have questions! In physics, it is essential that you understand these concepts before moving on.

## DISCUSSION: Frames of Reference

• Make sure you answer ALL questions in the prompt AND respond to two classmates.
• You will only earn a maximum of 70% if you do not thoughtfully respond to two classmates.

## QUIZ: Frames of Reference, Displacement, and Velocity

• Practice Problem 1:

A girl is on a train that is headed East at 100 miles per hour. The girl is walking at 5 miles per hour toward the back of the train. What is the speed and direction of the train if the girls is the frame of reference?

• ANSWER: The train is moving East at 100 miles an hour relative to the road. The girl is moving East at 95 miles an hour relative to the road. Since the road is "standing still", she would be moving the train's speed minus 5 mph because she is walking to the back of the train. The train is moving 0 miles an hour relative to the train because the train doesn't seem to be moving to the train (just like if you were sitting in the train next to a friend, the two of you would look stationary to each other). The girl is moving West at 5 miles per hour relative to the train because the train does not "notice" its own movement. The train is moving 5 miles per hour East relative to the girl because the girl is on the train, so she doesn't notice the the actual speed of the train. Kind of like how the Earth is spinning, but since we are on Earth, we don't notice that spinning and when cars are driving, we only count the speed of the car, not the speed of Earth and the car.

• Content Error: On the 4th slide on page 4, the slide should read as the image above (click on the image to make it larger)

• Content Error: On the 9th slide on page 5, the answer should be 5.8 m/s, NOT 6.2 m/s

## LAB: Velocity and Acceleration

• The lab handout can be found on page 6 of the content. You can view the lab rubric in the lab's dropbox folder. Following the rubric is the BEST WAY to make sure that you earn full points on your lab.
• Make sure you show your work on the two Calculation sections of the lab.
• I walk you through the lab here: https://youtu.be/eKQDH_4HWMo

• Opening the Moving Man Simulation: When you click on the link in the lab, it will take you to the Phet site. You will need to click "download" under the video to get the simulation. When you go to open the simulation, you may need to download an updated version of Java.
• What is the difference between experimental displacement and calculated displacement? Experimental displacement can be found within the simulation (see image above - click on the image to make it larger). Calculated displacement requires that you show your displacement calculations for each trial. In this lab, the experimental and calculated displacements will most likely be the same, at least for part a. It's to give you practice writing down both, since we will write down the calculated and experimental values a lot this semester.

• Q: I'm having trouble getting the site to work. What should I do?

• A: If your computer has issues with accessing the Phet activities you MUST get this straightened out in order to submit the work, and these labs are required with no alternative assignments available. Unfortunately, this is not something that I am able to help with, but a problem that you will need to find a solution to. If you wait until the day the assignment is due to try to access the site and you have problems, you will not be able to get the assignment submitted on time, so it is important that you access this site ahead of time so that you'll either know you don't have problems, or you will have time to get the problems fixed before the assignment is due. Being able to access this site and the activities there is a requirement of the course and it is your responsibility to make sure that you have access. This the help site for Phet: https://phet.colorado.edu/en/help-center/running-sims. This is a blog post that a parent shared with me. The information here enabled her son to solve his computer's problems: https://blogs.windows.com/msedgedev/2016/12/14/edge-flash-click-run/

• Q: I've tried everything. It still won't work. Help!
• A: Try the following:
7. The simulation should pop up when you click on the file you've just downloaded.
8. Watch this video: https://youtu.be/eKQDH_4HWMo and it will walk you through completing the lab.

Once you've gotten to where the simulation will appear on your computer, you will have everything set up for all of the other virtual labs and will not need to go through this process again.

## QUIZ: Acceleration and Motion Graphs

• Practice Problem 3C: For 3C, part of the area is above the zero line and part is below. If a velocity-time graph line goes below the zero line, this means the object was going backwards, or had a negative velocity. Since the problem wants displacement, not distance, we will have to take the difference of the two sections, which is what they've done in the answer key.

These graphs are kind of confusing. A lot of students expect if someone was going backwards then the graph would double back over on itself, but since the x-axis is time, the time in the scenario is always increasing and negative time doesn't really make any sense.

This site (http://www.physicsclassroom.com/class/1DKin/Lesson-4/Determining-the-Area-on-a-v-t-Graph) has good information about these types of problems.

• Practice Problem 4C (image above is for this question - click on the image to make it larger): The triangles and rectangles for calculating the area are always created based on the area between the data line and the 0 line on the x-axis. So even though the common way to say what we are looking for is "the area under the curve (line)" in this case, because our line is below zero, we are actually looking for "the area above the line and below zero."

## TEST: One Dimensional Kinematics

• A great way to study for the test is to go back and look at the quiz questions you missed.
• If the quiz has a short answer problem that makes you do math, you MUST show your work in order to earn full credit. What does showing your work look like? Read this!
• After you finish your test, be sure to review what you missed, and look for the News announcement outlining test correction procedures.

https://youtu.be/eKQDH_4HWMo
https://youtu.be/F73q7AbkgCg
https://youtu.be/lSTfBOqkcn8
1D Kinematics
Motion Vocabulary
Time and Displacement
Velocity
Solving an Easy Velocity Problem
Solving a Medium Velocity Problem
Solving a Hard Velocity Problem
Acceleration
Acceleration Due to Gravity
Solving Acceleration Problems
Other Acceleration Problems
Position-Time Graphs
Velocity-Time Graphs
They Might Be Giants - Speed and Velocity w/ Marty Beller
Displacement from time and velocity example | One-dimensional motion | Physics | Khan Academy
Felix Baumgartner's supersonic freefall from 128k' - Mission Highlights