Day 96
Goals: SWBAT...
1. solve a variety of momentum problems
2. ask questions when help is needed
3. work together effectively
4. Test crash barriers
Warm-Up 96 (5min):
Solve the following:
A 5,000 kg railroad car moving at 5 m/s collides into a stationary car with a mass of 45,000kg. If they couple together after the collision, what will be their combined velocity immediately after impact?
CLASSWORK
098A: Test crash barriers
- sign up next to ramp
098B: Momentum Review part 2
https://drive.google.com/file/d/0B-AiPYEb3nFVeXhISnl3XzdnU1k/view?usp=sharing
answers to Momentum Review part 2: https://drive.google.com/file/d/1hjzsudy1vc_xcc2tU9AABIf0qYDb0O3d/view?usp=sharing
098C: Momentum Review Part 3:
Solve 1-7, 9, 11-16, 18-22, 27, 30, 34, 46, 47
Exam tomorrow
lab due next week - more info on lab this thursday
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. 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
a tackle
CLASSWORK
095A: Crash Barrier Lab - Build Day
Show me your design, then collect your paper & glue gun.
Build your crash barrier.
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)
Due Thursday: 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?
Begin preparing for our Momentum exam, which will be Tuesday the 19th.
Complete a few of these each day between now and Friday. Due Friday. For problem #3, the there's a misspelling. Instead of "perfectly elastic", it should read, "perfectly inelastic"
https://drive.google.com/file/d/1jvrb1eP19ullDWktsYJIAM7264N2uBiL/view?usp=sharing