Day 95

Goals: SWBAT...

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

2. To explain, with theory and math, how to prove their crash barrier was successful/unsuccessful

Warm-Up 95 (5min):

1. Set the crash barrier firmness to 8, velocity to 10, click "go", and record the "maximum g's at impact"

2. Set the crash barrier firmness to 6, velocity to 10, click "go", and record the "maximum g's at impact"

3. Set the crash barrier firmness to 5, velocity to 10, click "go", and record the "maximum g's at impact"

4. What's the difference between the three trials?

5. Which trial of crash barrier do you want yours to resemble? Why?

http://www.mrwaynesclass.com/CrashBarrier/index.html

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CLASSWORK

095A: Crash Barrier Lab - Last Build Day

Check your design.

Document what you've done so far in a Google Doc shared with your groupmates.

Rate each component's success from 1 to 4.

Collect your paper & glue gun.

Build your crash barrier.

Revise if necessary

Don't burn yourself

from yesterday...

094A: Crash Barrier Lab

Today will be design day. Your task: Design a barrier which can safely stop a moving cart prior to it hitting the wall.

1. Create your google doc for your lab titled, "Lab 2: Crash Barrier Lab - Your Name", and share it with me.

2. Read the lab documents below.

3. 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.

4. 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)

5. 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?"

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

Learning at Home (HW)

More momentum review

095B: Momentum Review part 2

https://drive.google.com/file/d/0B-AiPYEb3nFVeXhISnl3XzdnU1k/view?usp=sharing

095C: Momentum Review Part 3:

Solve 1-7, 9, 11-16, 18-22, 27, 30, 34, 46, 47

https://www.physicsclassroom.com/reviews/Momentum-and-Collisions/Momentum-and-Collisions-Review-Answers

Due Tuesday: Intro to Analyzing Accelerometer Data

The goal of this HW is for you to get familiar with accelerometer software, and to analyze data from a control trial.

1. In the context of an experiment, "What's the purpose of a control?"

2. I'll be using the Sensor Kinetics App, which is available below. There are many sensors - I'm using the Linear Accelerator.

https://play.google.com/store/apps/details?id=com.innoventions.sensorkinetics&hl=en_US

https://itunes.apple.com/us/app/sensor-kinetics/id579040333?mt=8

3. The data for the control is below. For my control trial, I used no crash barrier. The cart just slammed straight into the wall. Find the spike red graph. What value does it measure? Estimate the magnitude (number) of the red data line at it's lowest point.

4. Looking at the y-data, what is the minimum y-value? Does this match your estimate from looking at the graph in #3 above?

Continue preparing for our Momentum exam, which will be Wednesday the 12th.

Complete a few of these each day between now and Wednesday.

https://drive.google.com/file/d/1jvrb1eP19ullDWktsYJIAM7264N2uBiL/view?usp=sharing

ESSENTIAL QUESTION: Momentum - Is It Conserved?

Goals: SWBAT...

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

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

3. To explain, with theory and math, how to prove their crash barrier was successful/unsuccessful

Warm-Up 95 (5min):

1. Can I test my crash barrier?

2. Can I modify my crash barrier?

3. What safety precautions must be considered for this lab?

From your old warm-ups...here as a resource...

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?

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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