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 crumples to increase the time of the collision
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
Want more crash videos? This one shows what we DON'T want - cabins which crumple and collisions which take a short amount of time: https://youtu.be/hFqZwMeJu9w?t=600
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 Collisions
Warm-Up 91 (5min): elastic and inelastic (need help? look at the HW notes from day 90)
1. What does 'deformation' mean?
action or process of changing in shape or distorting
2. Which kind of collision involves two objects bouncing off each other?
depending on the amount of deformation, inelastic (some deformation) or elastic (no deformation)
3. Which kind of collision involves two objects sticking to each other?
perfectly inelastic
4. In an elastic collision, what is conserved?
momentum, KE, mass
5. In an inelastic collision, what is conserved?
momentum, mass
6. Give an example of each of the following collision types:
a. elastic Billiard balls, air hockey pucks
b. inelastic any bouncing collision (bouncy ball, baseball/bat, orange/table
c. perfectly inelastic football players during a tackle
CLASSWORK
1. #091A: Inelastic 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 inelastic 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 (think of yesterday, and the ball bearings on the projector - what were the external forces we mentioned?), 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
091B: Perfectly Inelastic Collisions - What are they?
Take notes (https://www.flippingphysics.com/uploads/2/1/1/0/21103672/0183_lecture_notes_-_introductory_perfectly_inelastic_collision_problem_demonstration.pdf) and....
Answer Edpuzzle questions: https://edpuzzle.com/media/58864ac2fc574b4961343efd
Learning At Home / HW:
- Complete Classwork 91A
- 091B: Perfectly Inelastic Collisions
Take notes (https://www.flippingphysics.com/uploads/2/1/1/0/21103672/0183_lecture_notes_-_introductory_perfectly_inelastic_collision_problem_demonstration.pdf) and....
Answer Edpuzzle questions: https://edpuzzle.com/media/58864ac2fc574b4961343efd
- Practice Conservation of Momentum Quiz Thursday
- Real Conservation of Momentum Quiz Friday
WARM-UP (4 minutes)
1. What flows in a wire, positive or negative charges?
2. Look up a parallel circuit and a series circuit. Which did you create when you lit both bulbs?
3. What happened to the brightness of the bulbs when you lit both (AKA, compare the brightness when there was just one bulb, with two bulbs)
CLASSWORK
1. HW Review
2. Complete 090A and 090B: ~15 minutes
090A: Creating a Circuit (part 1)
You can work by yourself, or with one partner.
You'll get a single wire, 1.5V bulb, and 1.5V AA battery.
Your job: discover at least four different ways to complete a circuit
Procedure:
1. Predict a configuration of the materials that you think might light the bulb. (need ideas? LINK)
2. Test your configuration.
3. Using the Observation Form (see board), record a diagram of your prediction and whether or not the bulb lit.
4. Make and record other quantitative and qualitative observations (AKA, say why it .
5. Repeat steps 1–4 until you have identified at least 4 different ways the bulb will light and 6 different ways the bulb will not light.
090B: Creating a More Advanced Circuit (part 2)
RULE: ONLY USE ONE BATTERY
You will now combine materials with another person/group. That means you can use two bulbs, and up to two wires, but ONLY ONE BATTERY (more could overload the bulb, just like the LED yesterday, and I don't have any extra bulbs).
just like in #090A, create three configurations that light BOTH BULBS. Diagram them, as well as three configurations which don't work, and make observations.
091A: 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:
Activity 090A and 090B are due Friday.