ESSENTIAL QUESTION: Momentum - Is It Conserved?
Goals: SWBAT...
1. To consider how impulse and momentum are related to collision injury reduction
2. To identify the common components of a crash barrier
3. To design/build a crash barrier which reduces the impact force during a collision
4. (future goal) To explain, with theory and math, how to prove their crash barrier was successful/unsuccessful
Warm-Up 92 (3min):
1. Once I build it, can I test my crash barrier?
2. Once I build it, can I modify my crash barrier?
3. You'll be making your barrier out of 6 sheets of paper, and hot glue. What safety precautions must be considered for this lab?
From your old warm-ups...here are some resources...
Pics/video of barriers are below
What are the purpose of traffic barriers like this (LINK) or this (LINK) or this (LINK) or this (LINK)?
What do you think is inside those barriers?
How did a collision change the shape of this traffic barrier? Before: LINK After: LINK
Do you think the barrier in #3 did it's job? How can you tell?
football players duri
Videos showing how the above devices work:
Crash Cushions: http://www.barriersystemsinc.com/tau-ii-crash-cushion (video is on the right margin, halfway down the page, and is of a truck crashing head-on into the cushion)
Sand Barrels: https://www.youtube.com/watch?v=6Q1OzYtfQF0ng a tackle
CLASSWORK
092A: Crash Barriers: Core Components
Find the TAU II barrier.
Sketch it. Label the components. Describe each component and it's function in a list
Component Function
Nose Piece visibility
Diaphragm Containment. Keep Energy Cartridges lined up
Energy Absorbing Cartridge Take KE turn it into ThE, Sound, KE to move air in EAC's
Slider containment of EAC's, guide cars back into road
Cable hold parts together
Rear Anchor/Backstop The end. Keeps vehicle from going any farther
092B: Crash Barrier Project/Lab
Today will be your design day. Your task: Design a barrier which can safely stop a moving cart prior to it hitting the wall.
1. Read the lab documents below.
Lab Instructions: https://drive.google.com/file/d/0B-AiPYEb3nFVbmtCQy0zQnBlZVU/view?usp=sharing
Data Sheet: https://drive.google.com/file/d/0B-AiPYEb3nFVVWgwMW1rNHRiU3M/view?usp=sharing
2. Data: Your barrier can be a maximum of 60 cm long. The cart has a mass of 370g, a width of 6cm, height of 5cm, and length of 15cm. The ramp is 100cm long, 23cm high, and the angle of the ramp is 13.3 degrees.
3. EACH PERSON: Create a draft of your barrier with three scale drawings, top view, frontal view, and side view, and show it to me for approval. Note, if you'd like to be fancy, you can combine the frontal and side view drawings into an angled view like this (LINK)
4. Answer the question, "What features does your design include which make it the best for accomplishing the task of slowly stopping the cart before it hits the wall?"
Learning at Home (HW)
Begin preparing for our Momentum exam, which will be Wednesday the 12th.
Complete a few of these each day between now and then.
https://drive.google.com/file/d/1jvrb1eP19ullDWktsYJIAM7264N2uBiL/view?usp=sharing
Notebook check this Friday
Quiz on momentum conservation this Friday
Tutoring is available for physics every Thursday in the Library at 3pm
ESSENTIAL QUESTION: Momentum - Is It Conserved?
Goals: SWBAT...
1. Define Elastic, Inelastic, and Perfectly Inelastic Collision
2. To solve momentum conservation problems related to Inelastic & Elastic Collisions
Warm-Up 92 (5min): elastic and inelastic (need help? look at the HW notes from day 90 and 91)
1. Rank the three collision types from highest deformation to lowest deformation
2. Why is the following statement important when solving conservation of momentum problems? "when doing problems involving perfectly inelastic collisions, recall that the objects stick together after the collision"
3. Find the final velocity after a perfectly inelastic collision with two objects, both of mass 2kg, one with v=2m/s, the other with v=-6m/s
football players during a tackle
CLASSWORK
1. #092A: Elastic Collisions Activity
Purpose: To gather evidence that can be used to support a claim that total system momentum is or is not conserved in an elastic collision.
Background: The objects involved in a collision are often considered as a system. Provided that the system of two objects is not experiencing a net external impulse, there would be no change in momentum of the system. If one object within the system loses momentum, it is gained by the other object within the system. The combined momentum of both objects would be conserved.
Inelastic Collisions Interactive: https://www.physicsclassroom.com/Physics-Interactives/Momentum-and-Collisions/Collision-Carts/Collision-Carts-Interactive
2. #092B: Momentum and Impulse Practice Quiz
https://docs.google.com/document/d/1AOzEUF6tEp04fKQuRMjFcKv34VxRi7ADsK4M1czPnP4/edit?usp=sharing
Learning At Home / HW:
- Complete Classwork 92A
- 092C: Elastic Collisions. (I will check this for credit tomorrow)
Take notes (https://www.flippingphysics.com/uploads/2/1/1/0/21103672/0184_lecture_notes_-_introductory_elastic_collision_problem_demonstration.pdf) and....
Answer Edpuzzle questions: https://edpuzzle.com/media/5899e7d12907083e46c9dd03
- Physics Tutoring in the Library today at 3pm with Mr. Keith
- Real Conservation of Momentum Quiz Friday
WARM-UP (4 minutes)
Copy and Complete:
There are two requirements that must be met in order to establish an electric circuit. The requirements are
There must be an energy supply capable doing work on charge to move it from a low energy location to a ____ _____ location and thus establish an electric potential _________ across the two ends of the external circuit.
There must be a closed conducting loop in the external circuit that stretches from the ____ potential, positive terminal to the low potential, ________ terminal.
CLASSWORK
092A: How Well do You Understand Circuits?
1. COPY EACH SENTENCE, THEN COMPLETE IT WITH THE CORRECT WORD CHOICE. If an electric circuit could be compared to a water circuit at a water park, then the ...
... battery would be analogous to the ____.
... positive terminal of the battery would be analogous to the ____.
... current would be analogous to the ____.
... charge would be analogous to the ____.
... electric potential difference would be analogous to the ____.
Choices:
A. water pressure
C. water
E. water pump
B. gallons of water flowing down slide per minute
D. bottom of the slide
F. top of the slide
2. DRAW EACH DIAGRAM. Utilize your understanding of the requirements of an electric circuit to state whether charge would flow through the following arrangements of cells, bulbs, wires and switches. If there is no charge flow, then explain why not. DRAW EACH DIAGRAM.
a.
b.
Charge Flow: Yes or No?
Explanation:
c.
Charge Flow: Yes or No?
Explanation:
d.
Charge Flow: Yes or No?
Explanation:
Charge Flow: Yes or No?
Explanation:
3. The diagram at the right shows a light bulb connected to a 12-V car battery. The + and - terminals are shown.
a. As a - charge moves through the battery from A to D, it ________ (gains, loses) potential energy and ________ (gains, loses) electric potential. b. As a - charge moves through the external circuit from D to A, it ________ (gains, loses) potential energy and ________ (gains, loses) electric potential.
091A & 92B: Advanced Circuits & Components
What's a switch? What's a resistor? Capacitor? Transistor?
You likely know some of these terms, but not all.
We'll spend our last four days of class using, and learning about, the major components of circuit.
Things you'll do:
create real circuits that make lights flash, make sounds, etc.
diagram circuits using symbols
research circuit components, and describe their function
discuss what you've learned
Assignment: Learn about circuits components, and how they work, by completing "Switch On!" mini-labs
Assessment: You'll create two documents, both of which will be multiple pages long:
1. Lab Summary Doc (3 columns) : Mini-Lab Title; Circuit Diagram (AKA schematic); Concepts Illustrated in Lab
2. Circuit Components (4 columns): Component Name; Symbol; Function (what it does); How Does It Work?
Groups: 3-5 students per kit, depending on class size
HOMEWORK:
Video LINK
Questions:
Define the term "Resistance" (here's a photo of a resistor: http://usbflashrecovery.com/flash-drive-whats-inside/)
Write the equation for resistance, label each of the variables, and list the symbol (unit) for resistance
Copy the graph of V vs I for an ohmic material
Oop! Mr. P said that one of the equations you already wrote is called Ohm's Law. Put that title next to the appropriate equation.
Copy the graph of V vs I for a non-ohmic material
The non-ohmic graph is non-linear. Think about what that means... What happens to the current as the voltage increases?
Draw the diagram of the battery/lamp circuit, and the graph which goes along with it.
As PEele passes through the lamp, it gets converted into....what?
Watt (get it?) equation do we already know for power?
Copy & follow along as Mr. P derives the three equations for electric power. You may need to watch this section a few times to really get the connection between the equations.
Finally, the dimensions of power are....?
Extra Credit:
1. Complete #31-48 correctly LINK. Draw the diagrams, and use a different color pen or pencil to show the flow of current throughout the ENTIRE CIRCUIT. Due by Wednesday.
2. Other extra credit available this week. Complete "Switch On!" mini-labs #16-40 for extra lab points. Due by June 6th.
Seniors, your finals begin next week. Your review is here: LINK
Non-seniors, your finals begin Friday the 1st. Your review is here: LINK
For both groups, you may bring your equation sheet (AKA Table of Friends) to the exam. You should also bring a calculator, and a pen/pencil. As usual, no phones for calculators.