cudequest3

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= = toc =Chapter 3 Section 1=

What Do You See? 1
I see two crash dummies and the car crashed, I see the airbag is smashed into the adults face.

What Do You Think? 1

 * I think that if you wear a seatbelt and you have an installment of airbags, you should be a lot safer in a car in case you get in an accident.

Article http://archive.chicagobreakingnews.com/2010/01/cops-four-dead-in-car-accident-in-crest-hill.html
Four close friends are together in a car crash and killed saturday morning at Crest Hill. The reason the crash was caused was told by the police that they all were speeding. They all grew up together and sadly all died Crest Hill Police Chief Dwayne Wilkerson said speed may have been a factor in the crash, which is under investigation. According to their family and friends, the four friends who grew up in Romeoville were typically cheery and always having a good time. They are still in the works for typical equipment that wasn't working or investigating if they were not wearing seatbelts but we will find the true answer soon.

Investigate 1
1. 2a. Assistant Analysis: 11 out of 15 points 3.

(yes/no) || New Cars (1,2,3) || Vehicle Safety  people in vehicles are not the only ones in danger- pedestrians are too  manufacturers have to be aware of vehicle safety  not safe: no seat belts, chrome dashboards, solid steering columns  four wheel drive - more accidents maybe due to tendency of drivers to increase speed under the impression that the safety features will protect them
 * ** Safety features ** || Means of protection || Pre-1960 cars
 * seat belts || keeps driver and passengers inside of car. || no || 1 ||
 * head restraints || Protect from whiplash || no || 1 ||
 * front airbags || cushions during a collision || no || 1 ||
 * back up sensing system || Allows you to see what's behind you || no || 3 ||
 * front crumple zones || Absorb shock from crash. || no || 1,2 ||
 * rear crumple zones || Absorb shock from crash. || no || 2 ||
 * side-impact beams in doors || Absorbs shock from crash to the side. || no || 2 ||
 * shoulder belts for all seats || Protect you from jolting forward and hurting yourself || no || 1 ||
 * anti-lock braking systems (ABS) || helps maintain control/ prevents skid || no || 2 ||
 * tempered shatterproof glass || Protects glass from shattering. || yes || 1 ||
 * side airbags || If you crashed in the side, it can protect you. || no || 2 ||
 * turn signals || Allows other cars to see what direction you are turning. || no || 1 ||
 * electronic stability control || helps resist revolvers || no || 2,3 ||
 * energy-absorbing collapsible steering column || Prevents chest trauma || no || 1 ||
 * ===Physics Talk 1===

Checking Up 1
1. They have added seat belts, they got rid of hard chrome dashboard, and have had solid steering columns. 2. Two examples would be that the growing number of kilometers traveled by 4WD's and that drivers increase speed under the impression that the safety features will protect them.

=== Physics To Go 1 1. 10 safety features: turn signals (F,R,S), side airbags (S, T), tempered shatterproof glass (F,R,S,T), shoulder belts (F,R,S,T), side-impact beams in doors (S), rear crumple zones (R), front crumple zones (F), seat belts (F,R,S,T), head restraints (F,R), front airbags (F, R, T) 2. bike safety features: helmut, wrist guards, knee pads, reflector 3. in-line skating safety features: helmut, knee pads, wrist guards, shin guards, thick wheels 4. skate boards safety features: helmut, knee pads, wrist guards, a touch surface ===

What Do You Think Now? 1

 * Wearing seat belts and driving very cautiously can protect you from accidents, also the improvement on cars has really made driving safer so don't abuse the car adjustments. ||

 Investigate X2: Newton's FIrst Law and Seatbelts

 * Objectives:**
 * What happens to a passenger involved in a car accident without and with a seatbelt?
 * What factors affect the passenger’s safety after a collision?
 * How would a seat belt for a race car be different from one available on a regular car?


 * Hypothesis:**Respond to each of the above objectives fully.


 * With seatbelt will keep passenger from being tossed in the car, and without the passenger will go flying in the car.
 * Seat Belts, Location in the car, and speed of car.
 * Seat belts in race cars are much more secure, they hold you back in the car.


 * Materials:**List any materials used and draw a labeled diagram of your set-up (alternatively, include a snapshot or video).


 * Procedure:**
 * 1) Make a clay figure and then place the figure in the cart.
 * 2) <span style="margin-bottom: 0px; margin-left: 37pt; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px; text-indent: -19pt;">Arrange a ramp so that the endstop is at the bottom of the ramp.
 * 3) <span style="margin-bottom: 0px; margin-left: 37pt; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px; text-indent: -19pt;">Adjust the height of the ramp to make a very shallow incline.
 * 4) <span style="margin-bottom: 0px; margin-left: 37pt; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px; text-indent: -19pt;">Send the cart down the ramp.
 * 5) <span style="margin-bottom: 0px; margin-left: 37pt; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px; text-indent: -19pt;">Very gradually increase the height of the ramp until significant “injury” happens to your figure. Make a note of this height.
 * 6) <span style="margin-bottom: 0px; margin-left: 37pt; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px; text-indent: -19pt;">Fix your clay figure. Create a seatbelt for the figure and take a "Before" picture and post in your data table.
 * 7) Send your cart and passenger down the ramp at the same height as in Step 5. Be sure to record your observations specifically and carefully. Take an "After" picture and post in your data table to supplement your written observations.
 * 8) <span style="margin-bottom: 0px; margin-left: 37pt; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px; text-indent: -19pt;">Repeat Steps 6 and 7, using different types of material for the seatbelt.

**// Data and observations: //**

Injury Height with no seatbelt: .27 m through his body and sliced his neck. || 6 ||
 * **//Type of Seatbelt//** || //**Before Picture**// || //**After Picture**// || //**Description and Observations**// || //**Group**// ||
 * Thread || [[image:proringer:theadmadread.jpg height="192" caption="theadmadread.jpg"]] || [[image:proringer:thread_madread_2.jpg height="192" caption="thread_madread_2.jpg"]] || Arm chopped off. The seat belt cut
 * Wire || [[image:proringer:hershey_kissboybefore.jpg height="192" caption="hershey_kissboybefore.jpg"]] || [[image:proringer:hersheykissafter.jpg height="189" caption="hersheykissafter.jpg"]] || The wire was wrapped around him pretty tightly. The passenger was severely injured because the wire sliced through his arms and chest. It is clearly the thin dense material that did this || 1 ||
 * Yarn || [[image:proringer:bj_string_one.jpg height="192" caption="bj_string_one.jpg"]] || [[image:proringer:bj_string_twozel.jpg height="192" caption="bj_string_twozel.jpg"]] || Our observation of the string seat belt is that when the accident occurred, the figure slammed forward. This shows that the string is not sturdy enough to prevent an injury in an accident || 5 ||
 * String || [[image:proringer:stringlapoop.jpg height="192" caption="stringlapoop.jpg"]] || [[image:proringer:stringlapoop2.jpg height="192" caption="stringlapoop2.jpg"]] || Our seatbelt made of string went around the chest. After going down the ramp, our passenger was still in the cart without any injuries. || 2 ||
 * Ribbon || [[image:proringer:panso_x3_ribbon.jpg height="192" caption="panso_x3_ribbon.jpg"]] || [[image:proringer:panso_ribbon_x4.jpg height="192" caption="panso_ribbon_x4.jpg"]] || We made a seatbelt out of ribbon that went around his waist shoulders and chest. When the cart went down the ramp, the seatbelt held him in place and the clay person didn't leave the cart. || 3 ||
 * tape || [[image:proringer:mitchel_lalalal_masking.jpg height="192" caption="mitchel_lalalal_masking.jpg"]] || [[image:proringer:michell_lalal_2_masking.jpg height="192" caption="michell_lalal_2_masking.jpg"]] || we took a piece of tape and folded it over so there was no sticky part. We then twirled the end to make tying it easier. We put the tape belt around "her" waist and tied it around the bottom of the cart. Despite my face in the after picture, the tape actually worked well because our figure was unharmed and barely moved. ||

*Read the Physics Talk p268 - 271 before answering the following questions. *

Inertia- tendency to remain in the current state of motion Force- An influence on an object (push or pull) Pressure- continuous force applied on an object 2. In the collision, the car stops abruptly. What happens to the “passenger”? "He" keeps moving forward because of his momentum until a force stops him; be it a seat belt of the table. 3. What parts of your passenger were in greatest danger (most damaged)? The head. He typically flew downward off of the cart head first. 4. What does Newton’s first law have to do with this? The passenger keeps moving until something stops him. 5. What materials were most effective as seatbelts? Why? The thread kept the passenger from being bounced inside the cart. 6. Use Newton's first law of motion to describe the three collisions? An object in motion will continue in motion unless acted upon by an unbalanced force. 7. Why does a broad band of material work better as a seatbelt than a narrow wire? It has more surface on the body and thus applies less force on any specific area because it is distributed uniformly throughout the belt.
 * //Questions://**
 * // 1. Define the terms: inertia, force and pressure. //**

**// Conclusion: //** **//<span style="border-collapse: separate; font-style: normal; font-weight: normal; margin-left: 0.5in; text-indent: -0.25in;"> · Using Newton's First law of Motion, explain why a seat belt is an important safety feature in a vehicle. What factors affect the effectiveness of a seatbelt? What would you need to consider when designing a seatbelt for a race car? Use specific observations from this investigation to support your answers to these questions. //** **//<span style="border-collapse: separate; font-style: normal; font-weight: normal; margin-left: 0.5in; text-indent: -0.25in;"> · Explain at least 1 cause of experimental error. Be sure you describe a specific reason. //** **//<span style="border-collapse: separate; font-style: normal; font-weight: normal; margin-left: 0.5in; text-indent: -0.25in;">One specific example of error would be the cart is not going down the ramp steady. //** **//<span style="border-collapse: separate; font-style: normal; font-weight: normal; margin-left: 0.5in; text-indent: -0.25in;"> · How would you improve the results of this lab? (In other words, what would you change about the materials or procedure to eliminate or reduce the experimental error you describe above?) Have the dummy clay person hit an object after the crash to show how badly an accident could be without a seatbelt. //**

<span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;"> Investigate X3: Energy and Air Bags

 * Objective:**
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">How does an air bag protect you during an accident?


 * Hypothesis:** Respond to the objective fully.
 * It prevents you from flying out of the car and seriously hurting yourself.


 * Materials:** List any materials used and draw a labeled diagram of your set-up (alternatively, include a snapshot or video). **egg, flour, plastic bag, ruler, balance, bowl**


 * Procedure:**

**Note: //You may want to use the available technology to take "Before" and "After" pics to post in your data table to assist and elaborate on your written descriptions.//** // 1. Measure the height of your egg #1. // // 2. Place an egg in a ziplock bag, squeezing out all of the air in the bag before sealing. // // 3. Hold a ruler up on the table vertically. Hold the egg vertically at the 2 cm mark. (Keep the excess bag on top.) Drop it. Record your observations. // // 4. Hold the egg the same exact way at the 4-cm mark and repeat. Continue this process until the egg shell is slightly cracked. // // 5. Continue until the egg is smashed and the yolk leaks out. Measure the amount of egg still undamaged. How much of the egg is smashed? Be sure to record detailed observations. // // 6. Fill a bowl with rice and place the bowl inside of the box lid. // // 7. Measure the height of your egg #2. // // 8. Drop the egg from the smash height (Step 3). Measure the amount of egg sticking up out of the rice bed. How much of the egg is buried in the rice? Also, record your observations. // // 9. Repeat this, increasing the height in 2-cm increments until the egg is cracked, and then smashed. //

//**Data and observations:** Add more columns/row as needed.//


 * **Egg #** || **Drop Height (m)** || **Cracked or Smashed?** || **Description and Observations** || **Weight** (kg) || **Egg height** (m) || **depth into flour** (m) ||
 * 1 || 0.02 || very small crack || no visible crack, but audible one || 0.057 || 0.053 ||  ||
 * 1 || 0.04 || small crack || crack was visible and audible || 0.057 || 0.053 ||  ||
 * 1 || 0.06 || crack || crack was visible and audible, slight liquid seepage || 0.057 || 0.053 ||  ||
 * 1 || 0.08 || crack || hole in egg but membrane intact || 0.057 || 0.053 ||  ||
 * 1 || 0.1 || bad crack || top flattened || 0.057 || 0.053 ||  ||
 * 1 || 0.12 || bad crack || cracks are getting worse || 0.057 || 0.053 ||  ||
 * 1 || 0.14 || bad crack || cracks are really bad || 0.057 || 0.053 ||  ||
 * 1 || 0.16 || bad crack || cracks are really bad || 0.057 || 0.053 ||  ||
 * 1 || 0.18 || smashed || total annihilation || 0.057 || 0.053 ||  ||
 * 2 || 0.18 || nothing || nothing || 0.055 || 0.06 || 0.016 ||
 * 2 || 0.2 || nothing || nothing || 0.055 || 0.06 || 0.026 ||
 * 2 || 0.24 || nothing || nothing || 0.055 || 0.06 || 0.031 ||
 * 2 || 0.28 || nothing || nothing || 0.055 || 0.06 || 0.033 ||
 * 2 || 0.32 || nothing || nothing || 0.055 || 0.06 || 0.035 ||
 * 2 || 0.36 || nothing || nothing || 0.055 || 0.06 || 0.036 ||
 * 2 || 0.40 || nothing || nothing || 0.055 || 0.06 || 0.036 ||
 * 2 || 0.44 || nothing || nothing || 0.055 || 0.06 || 0.037 ||
 * 2 || 0.48 ||  ||   || 0.055 || 0.06 ||   ||
 * 2 || 0.52 ||  ||   || 0.055 || 0.06 ||   ||

0.041 m not cracked, 0.012 cracked
 * Calculations:** Show equation(s), numbers plugged in, and answer with correct units. Add columns in your data table to include these results.

GPE = mgh
 * What is the gravitational potential energy in each trial?


 * [[image:woods-wiki:111Picture_1.png caption="111Picture_1.png"]] ||
 * 111Picture_1.png ||

GPE = W
 * How much work is done in each trial?


 * [[image:woods-wiki:1111Picture_1.png caption="1111Picture_1.png"]] ||
 * 1111Picture_1.png ||

W = FD
 * How much force was used to stop the egg in each case of steps 5, 8 and 9.
 * W (J) || F (N) || D (m) ||
 * .106 || 6.625 || .016 ||
 * .118 || 4.54 || .026 ||
 * .141 || 4.55 || .031 ||
 * .165 || 5 || .033 ||
 * .188 || 5.37 || .035 ||
 * .212 || 5.89 || .036 ||
 * .235 || 6.35 || .037 ||
 * .259 || 7.19 || .036 ||
 * .294 || 7.95 || .037 ||
 * .353 || 8.825 || .04 ||
 * .412 || 11.14 || .037 ||
 * 1.764 || 39.2 || .045 ||

** *Read the Physics Talk p279 - 287 before answering the following questions. * **


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">This investigate is an analogy for a person in an automobile collision. What does the egg represent? What does the table represent? What does the rice represent?
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">
 * 3) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">the egg represents the person traveling in constant straight line motion in a car crash
 * 4) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">the table represents the windshield, dashboard, or hard surface in front
 * 5) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">the rice represents the airbag/cushion that acts as a non-dangerous unbalanced force


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Define the terms: Kinetic Energy and Work.
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">kinetic energy: the energy possessed by a moving body is called kinetic energy; KE = 1/2mv^2
 * 3) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">work: the amount of force applied on an object over a certain distance; W = F x d


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">What factors determine an object's kinetic energy?
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">mass (vehicle and its occupants)
 * 3) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">velocity of the object (velocity of vehicle)


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">When work is done on an object, what is the effect on the object's kinetic energy?
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Work can either increase the kinetic energy or decrease the kinetic energy depending on the direction of the applied force & the distance (displacement) that the object moves


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">How does the force needed to stop a moving object depend on the distance the force acts?
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">The object stopping the moving object needs to do Work and W = d x F
 * 3) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">greater the distance, lesser the force and vise-versa


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">What difference does a soft landing area make on a passenger during a collision?
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">the work done by a soft landing area decreases the kinetic energy of a person
 * 3) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">the KE of the person decreases and the energy of the soft landing increases


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">How does a cushion reduce the force needed to stop a passenger?
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Cushions are able to protect a passenger by extending the distance it takes to stop him/her in an accident.
 * 3) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">the stopping distance is larger and the force required to stop the passenger is smaller


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">What does the law of conservation of energy have to do with this?
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">an object in motion will stay in motion unless acted upon by an unbalanced force. In this case, the object in motion is the person and the unbalanced force is the airbag protecting the person.

Conclusion:


 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Using the law of conservation of energy, explain how an air bag can protect you during an accident. Use specific observations from this investigation to support your answers to these questions.


 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Because of the law of conservation of energy, a person in a car crash would stay in motion at constant speed unless stopped by an unbalanced force, which would be a hard windshield or dashboard. The hard surface would have to do work in order to stop the person and because the distance the person hits the surface is short, the force would be large. In order to decrease that large force, airbags increase the distance. (for lab substitute table for dashboard/hard surface, flour for airbag, and egg for person)


 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Explain at least 1 cause of experimental error. Be sure you describe a specific reason.
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">An experimental error would be due to the fact that flour changes its position in every trial and becomes compact. Therefore, the distance the egg was buried constantly changed and would decrease the distance by compacting to the bottom of the bowl.


 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">How would you improve the results of this lab? (In other words, what would you change about the materials or procedure to eliminate or reduce the experimental error you describe above?)
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">I would improve the results by changing the flour. Instead, I would use a puffy, inflated material like an airbag that has pretty consistent size/position and doesn't stay compacted/patted down.

Physics Talk 4
Newton's Second Law of Motion: if a body is acted on by an unbalanced force, it will accelerate in the direction of the unbalanced force. The acceleration will be larger for smaller masses. The acceleration can be an increase in speed, a decrease in speed, or a change in direction. Whiplash: the common name for a type of injury to muscles of the neck

Chapter 3 Section 5
Notes on momentum - quantity of motion described by the product of mass and velocity P = m(v) Large mass + small velocity small mass + large velocity large mass + large velocity

Physics To Go 5
1. The car that is at rest will travel further away from the car that hits it because it's speed is greater giving it more momentum. 4. Because the bigger mass will result in more momentum letting them push away people. 5. The speed and the mass, because if you combine both, whichever one has the greater momentum will not get knocked backwards. 6. The car would have to travel at 1 m/s because then both will have a momentum of 10,000 making their impacts equal.

** Objective: What physics principles do the traffic-accident investigators use to "reconstruct" the accident? **

 * They look at the mass and velocity of the objects involved in the investigation and use those numbers.

Materials: Ramp, motion detector, and 2 carts

Procedure:
 * 1) Place a motion detector at the right end of a track. Open up data studio. Dump "Velocity" into "Graph" display, and enlarge this.
 * 2) Place a cart on the middle of the track with the velcro to the right. Call this the "target cart." Place a second identical cart on the right end of the track. Call this the "Bullet cart".
 * 3) Click "Start" on Data Studio, and then push the bullet cart very gently towards the target cart so that they collide and stick together. You may need to practice this a few times. Be sure to get your body out of the way of the motion detector!
 * 4) Examine the graph produced by the motion detector. Using the Smart Tool, find the velocity right before and right after the collision. Record this in your data table.
 * 5) Vary the masses of the carts and repeat the process 5 times.

Data and observations: Add more columns/row as needed.
 * Mass of Bullet Cart (kg) || Mass of Target Cart (kg) || Speed of Bullet Cart(m/s) || Speed of Target cart (m/s) || Combined masses (kg) || Final Velocity of both carts (m/s) ||
 * 0.505 || 0.489 || 0.34 || 0 || 0.994 || 0.18 ||
 * 0.755 || 0.489 || 0.25 || 0 || 0.739 || 0.41 ||
 * 1.03 || 0.489 || 0.39 || 0 || 0.528 || 0.28 ||
 * 0.505 || 0.739 || 0.42 || 0 || 0.781 || 0.2 ||
 * 1.005 || 0.948 || 0.52 || 0 || 1.0 || 0.29 ||

Calculations: Show equation(s), numbers plugged in, and answer with correct units. Add columns in your data table to include these results.


 * Momentum of Bullet Cart || Momentum of Target Cart || Sums of Initial Momenta || Final Momentum ||
 * 0.505(0.34) = 0.1717 || 0.489(0) = 0 || 0.1717 ||  ||
 * 0.755(0.25) = 0.18875 || 0.489(0) = 0 || 0.18875 ||  ||
 * 1.03(0.39) = 0.4017 || 0.489(0) = 0 || 0.4017 ||  ||
 * 0.505(0.739) = 0.373195 || 0.739(0) = 0 || 0.373195 ||  ||
 * 1.005(0.948) = 0.95274 || 0.948(0) = 0 || 0.95274 ||  ||

**Questions:**


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Compare the initial momenta (calc 3) to the final momentum (calc 4). (Allow for minor variations due to uncertainties of measurement.)
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Except for the third trial, in all of the tests, the initial and final momentum were practically the same.


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">List the 6 types of collisions (top of page 312) and a brief description.
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">One moving object hits a stationary object and both stick together and move off at the same speed.
 * 3) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Two stationary objects explode by the release of a spring between them and move off in opp. directions
 * 4) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">one moving object hits a stationary object. the first object stops, and the second object moves off
 * 5) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">one moving object hits a stationary object, and both move off at different speeds.
 * 6) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">two moving objects collide, and both objects move at different speeds after the collision
 * 7) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">two moving objects stick together and move off at the same speed


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Which types of collisions are definitely inelastic? How do you know?
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">an inelastic collision is one where objects do not bounce off if each other, but rather move off together. Types 1 and 6 are inelastic.


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Which types of collisions are definitely elastic? How do you know?
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">an elastic collision is one where objects bounce off of each other. Types 2, 4, and 5 are definitely elastic.


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Define the law of conservation of momentum.
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">the total momentum before a collision is equal to the total momentum after the collision if no external forces act on the system.


 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Use the law of conservation of momentum to describe what happens when a cue ball hits the 15 balls in the middle of the pool table.
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">the sum of the momentum of all the balls right after the collision is equal to the momentum of the original cue ball. This is because nature conserves momentum. The objects may move in new directions and with new speeds, but the momentum stays the same.

Conclusion:
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Based on the law of conservation of momentum, how can the traffic-accident investigators use to "reconstruct" the accident? What does it mean to "conserve" momentum
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">If the investigators know the masses and velocities (momentum) of the vehicles before the collision, they can accurately display the masses and velocities (momentum) after the collision.
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">conserve means to maintain. By conserving momentum, the vehicles have the same momentum before & after a collision.


 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Explain at least 1 cause of experimental error. Be sure you describe a specific reason.
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">the flat track that the carts were being pushed around on was on a slight incline due to uneven materials on the bottom of the track. This could have offset the velocity, which is a key factor in calculating momentum.


 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">How would you improve the results of this lab? (In other words, what would you change about the materials or procedure to eliminate or reduce the experimental error you describe above?)
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">I would improve the results of this lab by using a track the was fully flat to the table with no incline. That way, the target cart would stay still on its own and the velocities would be more accurate.

Physics To Go 6
2. X--> <--X <--XX-->

2a. p=mv <span style="font: normal normal normal 13px/normal Arial; line-height: 19px; margin: 0px; padding: 0px;"> Cart A: =(1)(2) = 2 kg (m/s) <span style="font: normal normal normal 13px/normal Arial; line-height: 19px; margin: 0px; padding: 0px;"> Cart B = (1)(-2) = -2 kg (m/s)

2b. momentum before mvi + m2vi2 = P beofre (1kg)(2m/s) + (1kg)(-2m/s) 0 = Pbefore 2c. momentum after mvi + m2vi2 = mvf + m2vf2 (1kg)(2m/s) + (1kg)(-2m/s) = (1kg)(vf) + (1kg)(Vf2) 0 = 2kg(vf) 0 = Vf..... finally velocity of both carts is zero total momentum after the collision = 0.

3. mvi + m2vi2 = mvf + m2vf2 100vi+100vi = 100(4) + 100(4) 200vi=800 vi= 4 m/s

5. After they collide, vehicle B gains momentum (the 4000 kg(m/s) that vehicle A lost. The change in momentum is zero because although A loses momentum, it is transferred to B.

6. mvi + m2vi2 = mvf + m2vf (200kg)(3m/s) + (200kg)(2m/s) = 200Vf + 200Vf 1000 = 400 Vf 2.5 m/s = Vf

7. mvi + m2vi2 = mvf + m2vf2 80kg(10m/s) + (100kg)(8m/s) = 80kg(Vf) + (100kg)(9.78m/s) 622 = 80Vf 7.8 m/s = Vf

8. mvi + m2vi2 = mvf + m2vf2 (3)(2) + (1)(-2) = (3)(0) + (1)(Vf) 4 m/s = Vf

===<span style="font-size: 1.1em; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;">**Physics To Go 7** ===

<span style="font: normal normal normal 13px/normal Arial; line-height: 19px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;">4. You bend your knees when you jump to the ground so they act as a crumple zone. The bending decreases the force by increasing the distance, so you slow down. Otherwise, the impact would be strong enough to break your legs.

6a. m=1200 kg, Vi = 10 m/s F x t = m x deltaV Ft = 1200(0-10) -12,000 kg(m/s) to bring it to rest

6b. Ft = 1200(5-10) Ft = -6000 -6,000 kg(m/s) to slow it down to 5 m/s

7a. F = 10,000N, t = 1.2 s F x t = J 10,000 x 1.2 = 12,000 N(s)

7b. Ft = m(deltaV) 12,000 = 1200(deltaV) 10 m/s is the change in velocity

8. J = p F x t = mv F(.1) = 1500(5) F = 75,000 N

10. The area of the first force x time graph is larger. The greater the area, the greater the impulse, or change in momentum.