Ch3+MontantiJ

Jessica Montanti's Wikilog - Pd 6 CP Physics -Ms. Burns - 2010 Chapter 3 toc

Section 1
What do you see? There is a car crash test and the car is absorbing the impact and collapsing in the front. the driver is going forward and into an airbag. the teddy bear did not have a seat belt on and went flying.

how can you protect yourself from serious incidents if an accident were to occur? you should always wear your seat belt and be able to react to any occasion.

car crash: http://www.nydailynews.com/ny_local/2011/01/19/2011-01-19_driver_passenger_killed_when_car_crashes_into_median_in_the_bronx_police_say.html in this article a mini van crashed into a road barrier in the bronx. The passenger and the driver were both killed.

INVESTIGATE 1 2. a. I scored a 10 out of 15, which is a novice analyst. I was surprised about my results, however the true and false statements were extremely random and some of them I had never heard before while others were obvious answers. 3. a.

(yes/no) || New Cars (1,2,3) ||
 * ** Safety features ** || Means of protection || Pre-1960 cars
 * seat belts || keeps you in your seat during an accident. || no || 1 ||
 * head restraints || prevents whiplash || no || 1 ||
 * front airbags || cushions during a collision || no || 1 ||
 * back up sensing system || helps you safely back up and see blind spots. || no || 3 ||
 * front crumple zones || increase the time for when a distance occurs and reduces impact || no || 2 ||
 * rear crumple zones || increase the time for when a distance occurs and reduces impact || no || 2 ||
 * side-impact beams in doors || keep the doors intact, stiffening || no || 2 ||
 * shoulder belts for all seats || keeps the passenger safer || no || 1 ||
 * anti-lock braking systems (ABS) || help maintain control, prevent skids || no || 2 ||
 * tempered shatterproof glass || helps prevent cuts || yes || 1 ||
 * side airbags || keeps the passenger safer (head/torso collision) || no || 1 ||
 * turn signals || tells other drivers where the car is turning || yes || 1 ||
 * electronic stability control || helps resist rollovers || no || 2 ||
 * energy-absorbing collapsible steering column || prevents chest trauma || no || 1 ||

Physics Talk - Pedestrians are also at risk for car accidents. - Ralph Nader, an american attorney and political activist wrote a book //Unsafe at any speed// in 1965. This was a turning point for automobile history. The books discussed the problems with not having seat belts, chrome dashboards, and solid steering columns. - automobiles are safer when they have anti-lock rakes and four wheel drive, however some drivers relay too much on these features and end up in accidents.

PTG 1. 2. A bicycle would have breaks, a reflectors, two tires with an appropriate amount of air. The cyclists would have a helmet and could wear wrist guards or knee pads to ease their fall. 3. An inline skater could use a helmet, knee or wrist protectors. 4. A skate boarder would need a helmet, he could use knee protectors or wrist protectors to ease his fall.
 * seat belts || F & R ||
 * head restraints || F & R & S & T ||
 * front airbags || F & R ||
 * back up sensing system || R ||
 * front crumple zones || F & R ||
 * rear crumple zones || F & R ||
 * side-impact beams in doors || S ||
 * shoulder belts for all seats || S ||
 * anti-lock braking systems (ABS) || F ||
 * tempered shatterproof glass || F & R & S & T ||
 * side airbags || S & T ||
 * turn signals || S ||

Checking up 1. Seat belts, don't have hard chrome dashboards, and solid steering columns, side impact doors. 2. People feel they can depend on four wheel drive will protect them, so they may increase their speed and be less careful relaying on the car to protect them.

What do you think now? You should make sure you are driving a car that has airbags, seat belts, four wheel drive and turing signals. If your are on a skate board, skates, or a bicycle you can wear a helmet or padding to stay safe as well. It would be unsafe if you were to wear a helmet and padding while driving in a car.

Number 2 of Inquiring Further *extra credit Do an internet search for automobile safety features and ratings. You may wish to visit the national highway traffic safety administration web site. compare vehicles from different categories, such as vans, sports cars, or pick up trucks.

**Section 2**
 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?

- With a seatbelt a passenger is safe because they are strapped in, but when they are without a seatbelt the passenger can go flying out of the car. - A passengers collision is affected by whether or not they are strapped into the car by a seatbelt - A seatbelt for a race car would have more straps and be tighter and would also have a faster reaction time.
 * Hypothesis:** Respond to each of the above objectives fully.

clay, cart, ramp with end stop, wire, thread, string, yarn, ribbon, rubber bands, books, tissue box we used five books and a tissue box to make the ramp steep to send the clay person down the ramp enough that he would fall apart.
 * 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) Arrange a ramp so that the endstop is at the bottom of the ramp.
 * 3) Adjust the height of the ramp to make a very shallow incline.
 * 4) Send the cart down the ramp.
 * 5) Very gradually increase the height of the ramp until significant “injury” happens to your figure. Make a note of this height. = .365 meters
 * 6) 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) Repeat Steps 6 and 7, using different types of material for the seatbelt.

Data and observations: The track is built up with books and a tissue box to be high so that the passenger can be sent down an incline. Injury Height with no seatbelt: .365 meters

through his body and sliced his neck. || 6 ||
 * **//Type of Seatbelt//** || //**Before Picture**// || //**After Picture**// || //**Description and Observations**// || //**Group**// ||
 * Thread || [[image:activephysics-pvrhsd:111Photo_45.jpg height="240" caption="111Photo_45.jpg"]] || [[image:activephysics-pvrhsd:111Photo_46.jpg height="240" caption="111Photo_46.jpg"]] || Arm chopped off. The seat belt cut
 * Wire || [[image:proringer:hershey_kissboybefore.jpg width="236" height="178" caption="hershey_kissboybefore.jpg"]] || [[image:proringer:hersheykissafter.jpg width="242" height="182" caption="hersheykissafter.jpg"]] || - the injury was caused by the wire seatbelt because the wire sliced through his arms and chest. The wire material is clearly not a good solution to a material keeping people safe in the event of a collision. || 1 ||
 * String || [[image:activephysics-pvrhsd:stringgPhoto_86.jpg height="240" caption="stringgPhoto_86.jpg"]] || [[image:activephysics-pvrhsd:strringgPhoto_87.jpg height="240" caption="strringgPhoto_87.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 ||
 * Yarn || [[image:activephysics-pvrhsd:sgrant22221.jpg height="240" caption="sgrant22221.jpg"]] || [[image:activephysics-pvrhsd:sgrant11.jpg height="240" caption="sgrant11.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. ||   ||   ||   ||
 * Ribbon || [[image:activephysics-pvrhsd:Photo_38lp.jpg height="216" caption="Photo_38lp.jpg"]] || [[image:activephysics-pvrhsd:Photo_41lp.jpg height="192" caption="Photo_41lp.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 ||
 * Masking Tape || [[image:activephysics-pvrhsd:Photo_7758.jpg width="256" height="192" caption="Photo_7758.jpg"]] || [[image:activephysics-pvrhsd:Photo_7662.jpg width="256" height="192" caption="Photo_7662.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 || 4 ||
 * Masking Tape || [[image:activephysics-pvrhsd:Photo_7758.jpg width="256" height="192" caption="Photo_7758.jpg"]] || [[image:activephysics-pvrhsd:Photo_7662.jpg width="256" height="192" caption="Photo_7662.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 || 4 ||

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

Physics Talk - newtons first law of motion: an object at rest stays at rest, and an object in motion stays in motion in a straight line with constant speed unless acted upon by a net, external force.

- force is measured using a spring scale.

Questions:
 * 1) Define the terms: inertia, force and pressure. inertia: an object in motion to remain in motion, or a object at rest to remain at rest, unless acted upon by a force. force: an interaction between two objects that can result in an acceleration of either or both objects. pressure: force per area where the force is normal (perpendicular to the surface)
 * 2) In the collision, the car stops abruptly. What happens to the “passenger: The passengers body is launched forward.
 * 3) What parts of your passenger were in greatest danger (most damaged)?: The passengers whole body is at risk the wall exerts a force that brings all of the organs that are moving to rest.
 * 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;">What does Newton’s first law have to do with this?: Newtons first law of motion states than an object at rest stays at rest, and an object in motion stays in motion in a straight line with constant speed unless acted upon by a net, external force and this pertain to the car when it is stopped by the stopper.
 * 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;">What materials were most effective as seatbelts? Why? : the masking tape and ribbon because they are broader and the force is spread out.
 * 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;">Use Newton's first law of motion to describe the three collisions : First: the automobile strikes the pole, the pole exerts the force that brings the automobile to rest. Because the object will not stop moving until something hits it. Second: when the automobile stops, the body keeps moving. The structure of the automobile exerts the force that brings the body to rest. Third: The body stops, but the heart, the brain and other organs keep moving. The body wall exerts the force that brings the organs to rest.
 * 7) <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;">Why does a broad band of material work better as a seatbelt than a narrow wire? : The broad band is better because the force is distributed over more area.

Conclusion: · 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. - seat belts are important because they keep a passenger in their seat rather than flying out of their seat in a collision. - the materials it is made out of and the broadness of the seatbelt affect its effectiveness. - when designing a seatbelt for a race car you must make sure that the materials are appropriate like you would not want to use thin string or wire, a broad thick cloth would be more appropriate because the force would be more thoroughly distributed. · Explain at least 1 cause of experimental error. Be sure you describe a specific reason. - the body and cart could have not been pushed down from the height with the same force for each trial. · 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?) - To improve this lab next time I would use a spring for push the cart against each time in order to make sure the force is the same at every height.

USE THE RUBRIC TO MAKE SURE YOU HAVE INCLUDED ALL REQUIREMENTS!

<span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;"> Section 3
<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? : **An airbag protects you in an accident because it keeps your body from moving forward and keeps you in your seat safe, rather than flung out of a window.**

Hypothesis: Respond to the objective fully.

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

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 = **.053 cm** // // 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.: **At 2 cm the egg did not crack because the distance traveled was not large enough.** // // 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. : **At 4 cm the egg cracks a little bit at the bottom.** // // 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 cm: egg cracked and there is now a big dent 8:cm the egg cracked more. 10 cm: the egg cracked more and some yoke is starting to spill out. 12 cm:** // **the egg has a huge crack in its side, but the yoke is not completely spilling out yet.** **14 cm: t****he egg fell and the egg shells are now smashed and the yellow yoke is outside of the shell in the bag.** // 6. Fill a bowl with rice and place the bowl inside of the box lid. // // 7. Measure the height of your egg #2. **.056 meters** // // 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.// //**mass: .0582 kg first egg**// //**.059 kg first egg**//
 * **Egg #** || **Drop Height** || **Cracked or Smashed?** || **Description and Observations** || **Before** || **After** ||
 * 1 || 2 cm || nothing || no difference in the egg because the distance traveled was not enough || [[image:giordanowikilog:Photo_66.jpg height="144" caption="Photo_66.jpg"]] || [[image:giordanowikilog:Photo_66.jpg height="144" caption="Photo_66.jpg"]] ||
 * 1 || 4 cm || crack || the egg cracks a little bit at the bottom || [[image:giordanowikilog:Photo_66.jpg height="144" caption="Photo_66.jpg"]] || [[image:giordanowikilog:Photo_67.jpg height="144" caption="Photo_67.jpg"]] ||
 * 1 || 6 cm || crack || egg cracked and there is now a big dent || [[image:giordanowikilog:Photo_67.jpg height="144" caption="Photo_67.jpg"]] || [[image:giordanowikilog:Photo_68.jpg height="144" caption="Photo_68.jpg"]] ||
 * 1 || 8 cm || crack || the egg cracked more || [[image:giordanowikilog:Photo_68.jpg height="144" caption="Photo_68.jpg"]] || [[image:giordanowikilog:Photo_68.jpg height="144" caption="Photo_68.jpg"]] ||
 * 1 || 10 cm || crack || the egg cracked more and some yoke is starting to spill out. || [[image:giordanowikilog:Photo_68.jpg height="144" caption="Photo_68.jpg"]] || [[image:giordanowikilog:Photo_69.jpg height="144" caption="Photo_69.jpg"]] ||
 * 1 || 12 cm || crack || the egg has a huge crack in its side, but the yoke is not completely spilling out yet. || [[image:giordanowikilog:Photo_69.jpg height="144" caption="Photo_69.jpg"]] || [[image:giordanowikilog:Photo_70.jpg height="144" caption="Photo_70.jpg"]] ||
 * 1 || 14 cm || smashed || the egg fell and the egg shells are now smashed and the yellow yoke is outside of the shell in the bag. || [[image:giordanowikilog:Photo_70.jpg height="144" caption="Photo_70.jpg"]] || [[image:giordanowikilog:Photo_71.jpg height="144" caption="Photo_71.jpg"]] ||
 * 2 || 14 cm || nothing || the egg is fine and sticking out .037 meters and in .019 meters of flour || [[image:giordanowikilog:Photo_66.jpg height="144" caption="Photo_66.jpg"]] || [[image:giordanowikilog:Photo_72.jpg width="192" height="144" caption="Photo_72.jpg"]] ||
 * 2 || 18 cm || nothing || the egg still did not crack and is sticking out .029 meters and is buried in .011 meters of flour. || [[image:giordanowikilog:Photo_72.jpg height="144" caption="Photo_72.jpg"]] || [[image:giordanowikilog:Photo_72.jpg height="144" caption="Photo_72.jpg"]] ||
 * 2 || 22 cm || nothing || there is not crack and is sticking out.028 meters and buried in .012 meters. || [[image:giordanowikilog:Photo_72.jpg height="144" caption="Photo_72.jpg"]] || [[image:giordanowikilog:Photo_72.jpg height="144" caption="Photo_72.jpg"]] ||
 * 2 || 28 cm || nothing || with added flour it is sticking out .022 meters and buried in .018 meters still without a crack. || [[image:giordanowikilog:Photo_72.jpg height="144" caption="Photo_72.jpg"]] || [[image:giordanowikilog:Photo_73.jpg width="192" height="144" caption="Photo_73.jpg"]] ||
 * 2 || 36 cm || nothing || it is sticking out .018 meters and buried in .022 meters still without a crack. || [[image:giordanowikilog:Photo_73.jpg height="144" caption="Photo_73.jpg"]] || [[image:giordanowikilog:Photo_73.jpg height="144" caption="Photo_73.jpg"]] ||
 * 2 || 45 cm || nothing || it is sticking out .021 meters and buried in .019 meters still without a crack. || [[image:giordanowikilog:Photo_73.jpg height="144" caption="Photo_73.jpg"]] || [[image:giordanowikilog:Photo_73.jpg height="144" caption="Photo_73.jpg"]] ||
 * 2 || 60 cm || nothing || it is sticking out .019 meters and buried in .021 meters still without a crack. || [[image:giordanowikilog:Photo_73.jpg height="144" caption="Photo_73.jpg"]] || [[image:giordanowikilog:Photo_73.jpg height="144" caption="Photo_73.jpg"]] ||
 * 2 || 90 cm || nothing || it is sticking out .017 meters and buried in .023 meters still without a crack. || [[image:giordanowikilog:Photo_73.jpg height="144" caption="Photo_73.jpg"]] || [[image:giordanowikilog:Photo_73.jpg height="144" caption="Photo_73.jpg"]] ||
 * 2 || from ceiling to floor || cracked! || from the ceiling the egg completely cracked and was sticking out .01 meters and buried .03 meters || [[image:giordanowikilog:Photo_73.jpg height="144" caption="Photo_73.jpg"]] || [[image:giordanowikilog:Photo_74.jpg width="192" height="144" caption="Photo_74.jpg"]] ||


 * Calculations:** Show equation(s), numbers plugged in, and answer with correct units. Add columns in your data table to include these results.
 * <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 is the gravitational potential energy in each trial?
 * <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 much work is done in each trial?
 * <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 much force was used to stop the egg in each case of steps 5, 8 and 9. [[image:Picture_1.png height="220"]]

** *Read the Physics Talk p279 - 287 before answering the following questions. * ** Physics Talk - ke: kinetic eneryg: energy something has because of motion - w: f X d -


 * Questions:**
 * 1) <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;">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? : 1. T **he egg is the person traveling in constant straight line motion in a car crash. 2. T****he table is the windshield, dashboard, or hard surface in front. 3. T****he rice is the airbag/cushion that acts as a non-dangerous unbalanced force**
 * 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;">Define the terms: Kinetic Energy and Work. : **K** **inetic energy**: **the energy possessed by a moving body is called kinetic energy; KE = 1/2mv^2 W****ork****: the amount of force applied on an object over a certain distance; W = F x d**
 * 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;">What factors determine an object's kinetic energy? **the mass and the velocity of the object**
 * 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;">WHen work is done on an object, what is the effect on the object's kinetic energy? **Work can either increase the kinetic energy or decrease the kinetic energy depending on the direction of the applied force & the distance that the object is moving.**
 * 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;">How does the force needed to stop a moving object depend on the distance the force acts? **The object that is stopping the moving object needs to do Work and** **W = d x F. The** **greater the distance, lesser the force and vise-versa**
 * 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;">What difference does a soft landing area make on a passenger during a collision? : T **he work done by a soft landing area decreases the KE of the passenger during the collision. The KE of the passenger decreases and then energy of the landing increases.**
 * 7) <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;">How does a cushion reduce the force needed to stop a passenger? T **he cushion extends the distance a passenger has to stop when in an collision. The stopping distance is made larger and the force needed is made smaller.**
 * 8) What does the law of conservation of energy have to do with this? : This lab shows that **an object in motion will stay in motion unless acted upon by an unbalanced force. This pertains to a collision because the passenger is the object that is in motion and the airbag is the unbalanced force that serves as protection.**

· 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. : **The law of conservation of energy expresses how a person in a car crash against another car or a barrier the car will stay in motion at constant speed unless they are stopped by an unbalanced force like a windshield or dashboard. The hard surface that the passenger slammed into does work that stops the person from propelling forwards and if the distance the person hits the surface is short then the force will be greater. In order to decrease the large force, airbags are used as cushions to increase the distance. In our lab the flour was used an airbag and the egg was the person. The more flour the more distance and the less force.** · Explain at least 1 cause of experimental error. Be sure you describe a specific reason.: **An experimental error would be from the flour that changes its position in every trial. The distance the egg was buried constantly changed and varied and may not have provided accurate results. Also due to human error our measurements of the egg at each trial in the flour may not have been precise every trial.** · 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?) : **I would use instead an inflated material such as an airbag that has a more consistent size/position than the flour so it does not become compacted and does not vary in shape for each trial.**
 * Conclusion:**

<span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;"> Section 5
<span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;"> Physics To Go <span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;"> 1. Suppose an automobile collides with another automobile that is stopped. If both automobiles have the same mass, what do you expect to happen in resulting collision? **The automobile that is colliding into the other car will have a greater momentum because its velocity is greater than a car that is stationary.** <span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;">** 4. Why do football teams prefer offensive and defensive linemen who weight about 140 kg (about 300 lb)? They want heavier players because when the mass is great than the momentum will be also.** <span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;">** 5. What determines who will get knocked backward when a big vehicle collides with a smaller vehicle in a head-on collision? The one with the smaller momentum will be knocked backwards in a head-on collision (most likely the smaller vehicle)** <span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;">** 6. A 1000 kg automobile is moving at 10.0 m/s. At what speed would a 10,000-kg truck need to travel in the same direction so that the momentum of the two would be equal? P: mv P:(1000)(10) :10000 kg m/s 10000/10000= 1 m/s**

<span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;"> Section 6
<span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;"> **Investigate X6: Momentum and Inelastic Collisions**

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

Materials: List any materials used and draw a labeled diagram of your set-up (alternatively, include a snapshot or video). two carts, track, motion detector, masses

Procedure:
 * 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;">Place a motion detector at the right end of a track. Open up data studio. Dump "Velocity" into "Graph" display, and enlarge 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;">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) <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;">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) <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;">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) <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;">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)** || Initial Momentum Bullet Cart m/s(kg) || Final Momentum Both carts m/s(kg) || Initial Momentum Target Cart || Sum Initial Momentum Both ||
 * .498 || .501 || .62 || 0 || .999 || .28 || .31 || .28 || 0 || .31 ||
 * .498 || .9993 || .47 || 0 || 1.4973 || .14 || .23 || .21 || 0 || .23 ||
 * .9963 || .501 || .43 || 0 || 1.4973 || .14 || .43 || .21 || 0 || .43 ||
 * .995 || .9993 || .47 || 0 || 1.9943 || .18 || .47 || .36 || 0 || .47 ||
 * .995 || 1.2493 || .55 || 0 || 2.2443 || .23 || .55 || .52 || 0 || .55 ||


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

1. Find the initial momentum of the bullet cart for each trial. P=mv P = (.498 kg)(.62 m/s) P = .31 m/s(kg)

2. Find the initial momentum of the target cart for each trial. P=mv P=(.501kg)(0m/s) P = 0 kg(m/s)

3. Find the sum of the initial momenta of the two carts for each trial. initial momentum of Bullet Cart

4.Find the final momentum of the combined carts for each trial. P = mv P = (.999kg)(.28m/s) P = .28 kg(m/s)

** *Read the Physics Talk p312 - 315 before answering the following questions. * ** Compare the initial momenta (calc 3) to the final momentum (calc 4). (Allow for minor variations due to uncertainties of measurement.) <span style="font: 13.0px Arial; line-height: 19.0px; margin: 0.0px 0.0px 0.0px 72.0px; text-indent: -72.0px;">**For all the trials except the third the final and initial momentums were the same.** <span style="font-family: arial,helvetica,sans-serif; font: normal normal normal 13px/normal Arial; line-height: 19px; margin-bottom: 0px; margin-left: 72px; margin-right: 0px; margin-top: 0px; text-indent: -72px;">List the 6 types of collisions (top of page 312) and a brief description. Which types of collisions are definitely inelastic? How do you know?
 * Questions:**
 * **1) A moving object hits a stationary object and they stuck together and move forward at the same speed**
 * **2) Two stationary objects explode by the release of a spring between them and move off and opposite directions**
 * **3) One moving object hits a stationary object and the first object stops and the second moves forward.**
 * **4) one moving object hits a stationary object and they both move off in different speeds**
 * **5) two moving objects collide and they both move at different speeds after the collision**
 * **6) two moving objects stick together and move off at the same speed.**


 * **It is inelastic when the objects don't t bounce off of each other and stay and move together like types 1 &6.**

<span style="font-family: arial,helvetica,sans-serif; line-height: 19px;">Which types of collisions are definitely elastic? How do you know? Define the law of conservation of momentum. 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.
 * <span style="font: 13.0px Arial; line-height: 19.0px; margin: 0.0px 0.0px 0.0px 72.0px; text-indent: -72.0px;">**2, 4, & 5, because the objects are bouncing off each other.**
 * **It is the total momentum before a collision is equal to the total momentum after the collision if no external forces acts on the system.**


 * **The total momentum of the balls after the collision equal the momentum of the cue ball. The objects move in new directions but the momentum always remains the same.**

Based on the law of conservation of momentum, how can the traddic-accident investigators use to "reconstruct" the accident? What does it mean to "conserve" momentum Explain at least 1 cause of experimental error. Be sure you describe a specific reason. 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?)
 * Conclusion:**
 * **The investigators must know the masses and velocities of the vehicles because from here they can find the momentum, before the collision. From here they would be able to find out the same from after the collision. To conserve momentum the vehicles have the same momentum before and after a collision.**
 * <span style="font: 13.0px Arial; line-height: 19.0px; margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px;">**One cause would be the way the track was on the table because it was placed on a slight incline. That caused the carts to move when they were suppose to be stationary and this would affect the velocity and change the momentum.**
 * <span style="font: 13.0px Arial; line-height: 19.0px; margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px;">**I would improve the results by creating a flat surface so the cart would not move if not act upon by another mass.**

**PTG**

2. a) cart 1: p=mv p:1(2) =2 kg m/s cart 2: p:mv p:(1)(2) : 2 kg m/s m1v1+m2v2  (1)(2) + (1 1/2)(-2) 2 m/s -2 kg m/s b) 0 c) 0

3. mivi1 + m2v2 = mi1v1 + m2v2f m (vi) + 0 = m(4) + m(4) <span style="font-family: arial,helvetica,sans-serif;">v1= 8m <span style="font-family: arial,helvetica,sans-serif;">v1=8 m/s

5. Vehicle B gains the momentum, the exact amount is transferred so the change in the momentum is zero.

6. mivi1 + m2v2 = mi1v1 + m2v2f 2000(3) + 2000(2) = 4000vf 10,000= 4000vf 2.4 m/s = vf

7. m1vi1 + m2v2 = mi1v1 + m2v2f 80(10) +100(80) = 80vif + 100 (9.78) 800 + 800 = 80 vif + 978 1600 = 80 vif + 9 622 = 80 vif 7.8 m/s vif

8. m1vi1 + m2v2 = mi1v1 + m2v2f 3 (2) + 1(-2) = 3(0) + v2f 4 m/s = v2f

9. m:45 m2:75 v1: 0 v2: 0 m1vi1 + m2v2 = mi1v1 + m2v2f 45(0)+ 75(0): 45(-2) + 75vf 90 : 75vf vf : 1.2 m/s

10. m1: .35 kg m2: .06 kg v1: 20 v2 -30 vf: 10 v2f: ? m1vi1 + m2v2 = mi1v1 + m2v2f .35(20) + .06(-30)= (.35)(10) +.06 28.3 m/s : vf

11. m1vi1 + m2v2 = mi1v1 + m2v2f 3(0) + 1(4) : 3(2)+(1) vf 4: 6+vf vf: -2 m/s

12. m1vi1 + m2v2 = mi1v1 + m2v2f 90(0) + .16(30) : 90vf+.16vf 4.8 : 90.16vf vff: .05 m/s

13. m1vi1 + m2v2 = mi1v1 + m2v2f 45 (1.10)+.08(0)= 45vf+.08vf 49.5 : 45.08 vf vf: 1.09 m/s

14.m1vi1 + m2v2 = mi1v1 + m2v2f 1700 (10) +m(-25) : 1700(-5)+ m(-3.75) 17,000- 25m : -8500 -3.75m 25500: 21.25m 1200 kg

<span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;">**Section 7**
ptg 4,6,7,8,10

4. Explain why bend your knees when you jump to the ground? **You bend your knees when you jump to ground because you are lengthening the distance and thus decreasing the force that is being exerted. Bending your knees acts as the crumple zone like in a car so your legs are not hurt when they reach the ground.**

**<span style="font-family: arial,helvetica,sans-serif; font-weight: normal; font: normal normal normal 13px/normal Arial; line-height: 19px; margin: 0px;">6. An automobile has a mass of 1200 kg and an initial velocity of 10m/s. Calculate the change in momentum required to do the following= ** <span style="font-family: arial,helvetica,sans-serif; font: normal normal normal 13px/normal Arial; line-height: 19px; margin: 0px;">- Bring it to rest <span style="font-family: arial,helvetica,sans-serif; font: normal normal normal 13px/normal Arial; line-height: 19px; margin: 0px;"><span style="font-family: arial,helvetica,sans-serif;"> <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px;"> **p:mv** <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px;"> **1200(0-10)** <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px;"> **- 12000**

<span style="font-family: arial,helvetica,sans-serif; font: normal normal normal 13px/normal Arial; line-height: 19px; margin: 0px;"> - Slow it to 5 m/s
 * 12000/5**
 * 2400**

**<span style="font-family: arial,helvetica,sans-serif; font-weight: normal; font: normal normal normal 13px/normal Arial; line-height: 19px; margin: 0px;">7. If the breaking force for an automobile is 10,000 N, calculate the impulse if the brake is applied for 1.2 s. If the automobile has a mass of 1200 kg what is the change in velocity of the automobile over this 1.2 s time interval? ** **F (change in)T = m (change in v)** **10000 (1.2) = 1200 (change in)v** **12000 = 1200 v** **10 m/s = v**

8. A 1500 kg automobile traveling at 5 m/s after braking strikes a power pole and comes to a full stop in .1s. Calculate the force exerted by the power pole and brakes required to stop the automobile. **F (change in)T = m (change in v)** **F (.1) = 1500 (0-5)** **F (.1)= -7500 N**
 * F= -75000N**

** 10. compare and contrast the two force vs time graphs below ** **The first graph shows that because there is not a lot of time the force is greater, while the second graph shows a longer period of time so the force is smaller. The one with the bigger area will have the larger impulse and is more dangerous.**