DAY 93

Goals: SWBAT...

1. To design/build a crash barrier which reduces the impact force during a collision

WARM-UP

1. What must you do to decrease the impact force during a collision?

2. From the crash barriers we've observed, list one strategy or component you'll apply to your design.  

CLASSWORK

093A: Crash Barrier Project/Lab

Rubric: https://docs.google.com/document/d/1McoZKZf08il779ttJBONuoBZ92p8dqqDGuRJAAkUscA/edit?usp=sharing

Today will be your design/build 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?"

5. Common Pitfalls

    - barrier too rigid

    - doesn't make use of all 60cm of space

    - cart tunnels under barrier

    - speed bumps

    - 6 sheets of paper max

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 TOMORROW

Quiz on momentum conservation TOMORROW

    - Conservation of Momentum Practice Problems

LINK: https://drive.google.com/file/d/0B-AiPYEb3nFVZVJQekNiUjRGcG8/view

Answers: 

1.  mass

2.  isolated

3. . conserved      equal to

4. . Δp = 0 or pf = pi

5. . 

   1. a. velocity of ball 2 is 2m/s. All momentum transfers since the cue ball stops

   2. b. velocity of ball 2 is 1m/s. Both balls equally share the momentum, meaning the total is divided by 2

   3. c. velocity of ball 2 would be greater than 2m/s. The cue ball has negative momentum, therefore the momentum of ball 2 must be greater than the cue ball's original momentum (to keep the total the same and conserve momentum). 

6. A. 400kg m/s     B. 480kg m/s

7. A. pos     B. neg

8. +400 + -480 = -80kg m/s

9. -80kg m/s

10. 220kg

11. -0.36m/s

12. yes, the player moving left had a little more momentum than the player moving right, so the small leftward velocity makes sense

13. speed up a tiny bit, since the mass of a ladder is much less than the mass of a truck

14. no. again, the mass of a ladder is significantly less than that of a truck. 

ESSENTIAL QUESTION: Momentum - Is It Conserved?

Goals: SWBAT...

1. To consider how impulse and momentum are related to collision injury reduction

Warm-Up 91 (5min):

1. What are the purpose of traffic barriers like this (LINK) or this (LINK) or this (LINK) or this (LINK)?

2. What do you think is inside those barriers?

3. How did a collision change the shape of this traffic barrier? Before: LINK After: LINK

4. Do you think the barrier in #3 did it's job? How can you tell?

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=6Q1OzYtfQF0

CLASSWORK

1. 090C: Elastic Collisions. (I will check this friday during our notebook check)

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

2. 091A: Crash Video Analysis Activity

Handout LINK: https://drive.google.com/file/d/1QFijyB32T4C__Km5j80oTeDc4Z0ezgpO/view?usp=sharing

Link to videos: https://www.youtube.com/user/iihs/playlists

This is MY EXAMPLE. You can't borrow it...find your own :)

For example, if I watched this video: https://www.youtube.com/watch?v=-l8qdeU1-GU&index=133&list=PLEE778C8C6D7B7D43

I'd write...

Title: 1998 Volkswagen Passat Moderate Overlap IIHS Crash Test

Car Type: Midsize

Collision Type: Frontal, Moderate Overlap (which means, not the whole front, just part)

Safety Devices:                How It Worked:

Bumper                                you explain this...

Front Crumple Zone        

Front Airbag

Headrest

Padded Door

Safety Glass

We can compare that VW with an Audi that's 18 years newer: https://www.youtube.com/watch?v=dfG4SqPYcSA&list=PL012CE0AF5B6519E3&index=1

Learning at Home (HW)

Complete 91A

Notebook check this Friday

Quiz on momentum conservation this Friday

Student Survey: https://goo.gl/forms/0gNY06jPlOWVbOQV2

No Warm-Up. Sign out your Switch-On! kits and start learning :)

Classwork:

091A & 92B Continued: 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 (due Wednesday):

Video LINK

Questions:

1. Define the term "Resistance" (here's a photo of a resistor: http://usbflashrecovery.com/flash-drive-whats-inside/)

2. Write the equation for resistance, label each of the variables, and list the symbol (unit) for resistance

3. Copy the graph of V vs I for an ohmic material

4. 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.

5. Copy the graph of V vs I for a non-ohmic material

6. The non-ohmic graph is non-linear. Think about what that means... What happens to the current as the voltage increases?

7. Draw the diagram of the battery/lamp circuit, and the graph which goes along with it. 

8. As PEele passes through the lamp, it gets converted into....what? 

9. Watt (get it?) equation do we already know for power? 

10. 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. 

11. 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.