Safety-Chapter+3

= Nichole Formicola's Wikilog - Period 8 CP Physics - E. Burns - 2010 = toc = =

CHAPTER 3: SECTION 1
I see a car crashing into a roadblock. The car hits the roadblock and the airbag comes out of the steering wheel and hits the dummy. The front of the car is smashed in and things are flown out of the car. This must be a test run, because there is a dummy and there is a spring on the back of the car, meaning it might have been launched forward. There is a child in the back seat too, to show that the kid is safe when the car is crashed. Make sure all airbags are on. Also sit in the correct seat (if you are young:sit in a car seat). Also, always wear your seat-belt and try to make sure you are paying attention so that you know what is happening.
 * WHAT DO YOU SEE: **
 * WHAT DO YOU THINK: **

**PHYSICS TALK SUMMARY:** Governments and of automobiles can work together to make vehicles safer. A turning point in the history of automobile safety occurred when Ralph Nader, and American attorney and political activist, wrote the book Unsafe at Any Speed in 1965. An australian study of 4-wheel drive found that the incidence of fatal 4WD crashes increased by 85 percent between 1990 and 1998. The incidence of all fatal crashes decreased 25 percent between 1990 and 1998. This increases in fatal 4WD crashes could be due to the growing number of kilometers traveled by 4WDs. It could also be due to the tendency of some drivers to increase speed under the impression that the safety features will protect them. Automobiles with anti-lock brakes and four wheel drive should be safer than automobiles without these features. Some drivers may overcompensate for these added features and end up in accidents that could have been avoided it they had just slowed down.

1) Four-wheel drive Anti-lock braking system  seat belts  2) This increase in fatal 4WD crashes could be due to the growing number of kilometers traveled by 4WDs. It could also be due to the tendency of some drivers to increase speed under the impression that the safety features will protect them
 * CHECKING UP QUESTIONS: **

1)
 * INVESTIGATE: SECTION 1 **

2a) I was not surprised because those questions are not something that we are taught to know. Everyone has their own ideas about safety, but I do not look up the statistics about death rates.

3) (yes/no) || New Cars  (1,2,3) ||
 * ** Safety features ** || Means of protection || Pre-1960 cars
 * seat belts || To keep a person/driver from coming out of their seat in case of an accident. To keep them in the car || no || all automobiles ||
 * head restraints || Keep head stable, so that it does not snap back || no || all automobiles ||
 * front airbags || To keep you from smashing into the dashboard or flying out of a window || no || most automobiles/optional can turn on and off ||
 * back up sensing system || To guide you when going in reverse, so that you do not hit something behind you since not everything is visible || no || most cars, it is optional ||
 * front crumple zones || increase collision distance reducing impact || no || 1,2,all,some ||
 * rear crumple zones || increase collision distance reducing impact || no || 1,2,all,some ||
 * side-impact beams in doors || resits side penetration || no || 2,some ||
 * shoulder belts for all seats || keeps passengers in seats during collision || no || 1,all ||
 * anti-lock braking systems (ABS) || helps maintain control/prevents skids || no || 2,some ||
 * tempered shatterproof glass || So that in case of a crash, glass does not cut anyone or go anywhere || no || 2,some ||
 * side airbags || So you do not smack into the side of the car, protects head/torso in side collisions || no || 2,som= ||
 * turn signals || So that you can tell the person behind you or the people around you where you are going, so that they can react to the situation || yes || yes ||
 * electronic stability control || helps resits rollovers || no || 2.3.some,few ||
 * energy-absorbing collapsible steering column || prevents chest trauma || no || 1,all ||

1) -seat-belts: F, R, S, T -airbags: F, S -back up sensing system: R -turn signal: F, R, S -energy absorbing steering column: F, R, S, T -head restraints: F, R -anti-lock braking system: F -front crumple: F -rear crumble: R -shoulder belts: F, R, S, T 2) - turn signals, helmets, knee pads, face guard, lights 3) - helmet, protective gear, brakes, crumble system 4) - brakes, helmet, protective gear
 * PHYSICS TO GO: **

1) 2)
 * INQUIRING FURTHER: **

You can protect yourself from a serious injury when in a car accident, by making sure you have all the high-tech safety equipment a car should have. Also, wear your seat-belt at all times and make sure that you have an airbag on and that you are in the correct seat that you should be in. Also, follow the rules of driving and beware the risks if you don't. Follow the speed limit, and do not take advantage of your safety equipment in your car. You never know when you are going to be in an accident, so the only thing you can do is make sure you are prepared when getting into the car to limit your injury in case of this situation.
 * WHAT DO YOU THINK NOW: **

CHAPTER 3: SECTION 2
There is a blue and a red car. The blue car hits into a road block, but has a seat belt on. The red car does not have a seat-belt in the car and does not have a steering wheel that is absorbing, so him and the steering wheel fly out of the car, when they hit into the back of the blue car. The dummy in the blue car stays in the car and the only think damaged is the front and back of the car.
 * WHAT DO YOU SEE: **

The seat-belt should be wider and bigger, so that it has more control over the rest of the body. The seat belt should have an anti-lock system so that if it crashes the seat-belt does not keep going with the speed of the car. Also, make the seat-belt of a thicker fabric, so that it does not break. Also, there should be an easy access to get out of the seat-belt just in case the have to get out of the car quickly when crashed.
 * WHAT DO YOU THINK: **

Newtons first law of motion states that an object at rest stays at rest, and an object in motion stay in motion in a straight line with constant speed unless acted upon by a net, external force. There are three collisions in an accident, the first collision is when the conveyance strikes an object and it rapidly decelerates. The second collision is when the occupants are still moving at constant speed, and will continue to do so until they are stopped by striking the interior parts of the automobile or ejected out of the car. The third collision is when the brain and body organs have also been moving at the same speed and will continue to do so until they are stopped by colliding with the shell of the body. First Collision: The automobile strikes the pole. The pole exerts the force that brings the automobile to rest Second Collision: When the automobile stops, the body keep moving. The structure of the automobile exerts the force that brings the body to rest Third Collision: 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. Different seat belts have different affect on different people. Force that is spread out over a given area is called pressure. Pressure is defined at force per unit area. It is the pressure, not the force, that determines how much damage the seat belt does to the body.
 * PHYSICS TALK SUMMARY: **

1) Newtons first law of motion states that an object at rest stays at rest, and an object in motion stay in motion in a straight line with constant speed unless acted upon by a net, external force 2) The driver stays in motion until it comes in contact with a force to stop it, which is an interior part in the car. 3) __First Collision:__ The automobile strikes the pole. The pole exerts the force that brings the automobile to rest Second Collision: When the automobile stops, the body keep moving. The structure of the automobile exerts the force that brings the body to rest __Third Collision:__ 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.
 * CHECKING UP QUESTIONS: **

4) Inertia is the natural tendency of an object to remain at rest or to remain moving with constant speed in a straight line. 5) The narrow wire just dug into the clay passenger, because of the pressure on the area where the wire came in contact with. The bigger the material, the more spread out the pressure is on the person.

**Investigate X2: Newton's First Law and Seat-belts**

 * Objectives:**
 * What happens to a passenger involved in a car accident without and with a seat-belt?
 * 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?

A passenger without a seatbelt who is involved in a car accident is more likely to get more severe injuries than a person who is wearing a seatbelt. They could be thrown out of the car or hit into the dashboard, since their is no safety precautions. The factors that affect a passengers safety after a collision in the safety that is throughout the car. The seat-belt for a race car would be different, because race car drivers need something that can hold them in for a faster speed. Their seat-belt should go around both of their arms instead of just over their chest, something that is more sturdy that cannot move or become bigger.
 * Hypothesis:** Respond to each of the above objectives fully.

- a ramp - a cart to go down the ramp - a clay dummy
 * Materials:** List any materials used and draw a labeled diagram of your set-up (alternatively, include a snapshot or video).

Make a clay figure and then place the figure in the cart. Arrange a ramp so that the end stop is at the bottom of the ramp. Adjust the height of the ramp to make a very shallow incline. Send the cart down the ramp. Very gradually increase the height of the ramp until significant “injury” happens to your figure. Make a note of this height. Fix your clay figure. Create a seat-belt for the figure and take a "Before" picture and post in your data table. 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. Repeat Steps 6 and 7, using different types of material for the seat belt.
 * Procedure:**

BEFORE: GOING DOWN THE RAMP: media type="file" key="antrialseatbelt.mov" width="300" height="300"
 * Textbook # || Height || Injury ||  ||   ||   ||   ||
 * 2 || 8 cm |||||| fell off of cart/back adjusted ||  ||   ||
 * 3 || 12 cm |||||||| fell off of cart/back slightly moved again ||  ||
 * 4 || 16 cm |||||||| did a flip off of car and dented his head ||  ||
 * 5 || 21 cm |||||||| flipped over and landed on his arm and head ||  ||
 * 6 || 25 cm |||| major head trauma ||  ||   ||   ||
 * 7 || 28 cm |||||| legs were smashed along with head ||  ||   ||
 * 8 || 31 cm |||||||||| legs were bent and back was bent along with smashed head ||

AFTER:

Questions: 1. Define the terms: inertia, force and pressure. 2. In the collision, the car stops abruptly. What happens to the “passenger”? 3. What parts of your passenger were in greatest danger (most damaged)? 4. What does Newton’s first law have to do with this? 5. What materials were most effective as seat belts? Why? 6. Use Newton's first law of motion to describe the three collisions. 7. Why does a broad band of material work better as a seat belt than a narrow wire?
 * Inertia is the natural tendency of an object to remain at rest or to remain moving with constant speed in a straight line. Force is a push or a pull; an interaction between two objects that can result in an acceleration of either or both objects. Pressure is a force per area where the force is normal (perpendicular) to the surface; measured in N/m^2 or Pa**
 * The passenger's body will have three different collisions until there is no more inertia**
 * The head, back, legs and arms**
 * An object in motion will remain in motion unless acted upon by an unbalanced force (the collision) and when all of the collisions end there is normally damage done to the person's body.**
 * These materials were most effective because they were the strongest material possible.**
 * A. an object at rest stays at rest**
 * B. an object in motion stays in motion in a straight line with constant speed**
 * C. this part says part one and two are only true when the net force on the object is 0**
 * There is more mass to stop an even bigger mass.**

Conclusion: **Newton's First Law of Motion states that an object at rest stays at rest and an object in motion stays in motion with the same speed in the same direction unless acted upon by an unbalanced force. ****So when a person gets into a car accident, a seatbelt can save a life. They stop the motion of the person as they are moving so that they don't go through the window or windshield. When designing a seat belt for a race car I would make it strong enough to hold a person with a big mass that is going at an extremely fast speed so that it is most effective for everyone. One cause of an experimental error could be not measuring the height of the books correctly. More advanced technology could be used to make the lab more efficient such as computerized calculations for the speed and measuring the mass exactly of each object on a person so it is entirely accurate.**

Since the clay model is made out of a sticky material, it could have stuck to the cart giving it a bigger advantage to stay in the cart. Also, the tape could have been tighter around the clay model, but it is hard to form a seat belt to clay model, because not everything is proportionate. I would change the material of object, so that the model could not have stuck to the cart and could have been proportionate. Also, the ramp should have been set at the same height for all of the groups, so that we all could have gotten measurements for the same height with different materials.
 * 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?)**

**Investigate X3: Energy and Air Bags**

 * Objective:**
 * How does an air bag protect you during an accident?

An air bag protects you during an accident, because the air bag cushions your impact, so that you do not slam into something really hard. If there was not airbag, than you would slam into the dashboard and have nothing to slow your impact. The airbag comes out and reduces your impact
 * Hypothesis:** Respond to the objective fully.

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

//**Data and observations:** Add more columns/rows as needed.//
 * **Egg #** || **Dropped Height** || **Cracked or Smashed?** || **Description & Observations** ||
 * 1 || 2 cm || crack || there was a very tiny hairline crack on the bottom of the egg. no yolk came out ||
 * 1 || 4 cm || crack || crack got bigger, there is still no yolk ||
 * 1 || 6 cm || crack || egg is starting to break more. there are multiple cracks ||
 * 1 || 8 cm || crack || there are more indents and more noticeable cracks ||
 * 1 || 10 cm || crack || the bottom is becoming flattened and the cracks are moving towards the center of the egg ||
 * 1 || 12 cm || crack || yolk is starting to show and there are a lot of cracks ||
 * 1 || 14 cm || crack || there is some yolk coming out ||
 * 1 || 16 cm || smashed || the bottom of the egg is smashed and there is a lot of yolk coming out ||
 * 1 || 18 cm || smashed || the yolk continues to pour out at the height is now 5 cm ||
 * 1 || 20 cm || smashed || the yolk is still coming out and the height is now 4.8 ||
 * 1 || 22 cm || smashed || the yolk is almost out but not quite ||
 * 1 || 24 cm || smashed || part of the shell is almost off, the yolk is coming out and the height is now 4.4 cm ||
 * 1 || 26 cm || smashed || the yolk has not come out yet, but the egg is smashed. it is now 3.9 cm ||
 * 1 || 28 cm || smashed || parts of the shell fell off and the egg is now 3.7 cm ||
 * 1 || 30 cm || smashed || 3 cm, yolk is almost out ||
 * 1 || 32 cm || smashed || the egg is completely smashed and the yolk is out. the height is 2.6 cm ||
 * 2 || 32 cm ||  || Buried: 1.5 cm Above: 3.5 cm ||
 * 2 || 34 cm ||  || Buried: 1 cm Above: 4 cm ||
 * 2 || 36 cm ||  || Buried: 1.7 cm Above: 3.2 cm ||
 * 2 || 38 cm ||  || Buried: 2 cm Above: 3 cm ||
 * 2 || 40 cm ||  || Buried: 2. 3 cm Above: 2.7 cm ||
 * 2 || 42 cm ||  || Buried: 2.8 cm Above: 2.4 cm ||
 * 2 || 44 cm ||  || Buried: 1.6 cm Above: 3.4 cm ||
 * 2 || 46 cm ||  || Buried: 2.4 cm Above: 2.6 cm ||
 * 2 || 50 cm ||  || Buried: 1.7 cm Above: 3.2 cm ||
 * 2 || 60 cm ||  || Buried: 3 cm Above: 2 cm ||
 * 2 || 70 cm ||  || Below: 3.5 cm Above: 1.7 cm ||
 * 2 || 80 cm || cracked || Below: 3.4 Above: 1.8 cm ||
 * 2 || 85 cm || cracked || Below: 3.8 Above: 1.4 cm ||
 * 2 || 90 cm || cracked || Below: 2.5 cm Above: 2.5 cm- yolk is visible ||
 * 2 || 95 cm || cracked || Below: 2.5 cm Above: 2.5 cm- yolk is out ||


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

** *Read the Physics Talk p279 - 287 before answering the following questions. * ** The egg represents the person in the car. The table represents the collision. The flour represents the air bag KE=1/2mv^2. Kinetic energy is the energy obtained by a moving object. Work=FD. Work is the force applied over a certain distance. The factors that determine an objects kinetic energy are the mass and the velocity of the object because those are the components of the equation KE=1/2mv^2. 4. **When work is done on an object, what is the effect on the object's kinetic energy?** Work can either increase or decrease the kinetic energy. This depends upon the direction the object is moving in. If the work is moving in the same direction as the object, it can increase it. If the work is acting in the opposite direction stopping the object, it decreases kinetic energy. The object stopping the moving object is work. The less the distance, the greater the force. The work done on a soft landing area decreases the kinetic energy of the object. The area of the soft landing lowers the damage of the impact, because with a hard landing the object with just crash, with a soft impact it allows the object to have some cushion. The cushions apply padding and more room for the person to move with. It also increases the distance for the person to stop, because the cushion moves back and forth. The stopping distance is greater. And the force required decreases Newton's first law states that an object in motion or rest stays in motion or rest until an unbalanced force acts upon it. The person is the object in motion and the airbag is the unbalanced force stopping the person from hitting the dashboard or even falling out of the car. · 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?) ==
 * Questions:**
 * 1.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 flour represent?**
 * 2. Define Kinetic energy and work**
 * 3. What factors determine an object's kinetic energy?**
 * 5. How does the force needed to stop a moving object depend on the distance the force acts?**
 * 6. What difference does a soft landing area make on a passenger during a collision?**
 * 7. How does a cushion reduce the force needed to stop a passenger?**
 * 8. What does the law of conservation of energy have to do with this?**


 * Investigate X5: Momentum and Elastic Collisions **

==

Objective: A small sports car hits a heaby truck in a collision. What factors determine the outcome for the passengers of the two vehicles? Which driver will sustain worse injuries? Why? **The mass of the two cars, and the speed of the two cars will determine the outcome for the passengers. The driver in the small sports car will have worse injuries because it is a smaller mass and will have less momentum.**

Materials: **Cart without spring, cart with spring, 500 g masses, and a ramp**.

Procedure:
 * 1) Place a cart on the middle of the track with the spring 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".
 * 2) Push the bullet cart very gently towards the target cart so that they collide, with the spring between them.
 * 3) Repeat step 2 several times, giving the bullet cart a bigger push each time. Record your observations.
 * 4) Add 500-g to each cart and repeat the process. Record your observations and compare the results to the first set of collisions.
 * 5) Remove the mass from the target cart and repeat the above steps.
 * 6) Add the mass to the target cart and remove the mass from the bullet cart, and repeat.
 * 7) Get the "Mystery" cart from your teacher. Determine the relative mass of the cart by putting it through a sequence of collisions.

//**Data and observations:** Add more columns/row as needed.//
 * **Bullet Cart** || **Target Cart** || **Applied force** || **Description and Observations** ||  ||
 * 500 g || 500 g || small || bullet cart stayed in place where it came in contact with target cart while the target cart ricochet off the bullet cart until momentum ended ||  ||
 * 500 g || 500 g || medium || the same beginning actions occurred but the target cart moved farther than last time because there was more force. ||  ||
 * 500 g || 500 g || large || the bullet cart continued to move a little after it hit the target cart. the target cart hit the end of the ramp and ricochet off the rubber and bounced back. ||  ||
 * 1000 g || 1000 g || small || the bullet cart stopped when it hit the target cart and the target cart moved slightly ||  ||
 * 1000 g || 1000 g || medium || the bullet cart continued to move after it hit the target cart and the target cart moved more than it did with a small force. ||  ||
 * 1000 g || 1000 g || larger || the bullet cart continued to move until it hit the target cart a second time and the target cart was pushed twice. ||  ||
 * 1000 g || 500 g || small || the bullet cart moved a little after it hit the target cart and the target cart moved farther than it did before because it weighs less ||  ||
 * 1000 g || 500 g || medium || the bullet cart kept moving after it hit the target cart because the target cart is lighter in mass and does not apply enough force to stop it. ||  ||
 * 1000 g || 500 g || large || the target cart bounced multiple times after the bullet cart hit it repeatedly ||  ||
 * 500 g || 1000 g || small || the bullet cart stopped as soon as it hit the target cart and the target cart moved for a longer time compared to other small applied force ||  ||
 * 500 g || 1000 g || medium || the bullet cart stopped again and the target cart moved farther ||  ||
 * 500 g || 1000 g || large || the bullet cart stopped immediately again and the target cart moved farther again ||  ||
 * After putting the mystery cart through a series of tests with and without extra weight we can determine that it is most likely more than 2000 grams. We added more and more mass while applying the same amount of force as our lab (small, medium and large) and compared the movements with our observations.**

1. What is a real-life collision that the collisions in this investigation could represent? 2. How well did observing collisions enable you to compare the masses of the carts in the last step? 3. What happened after the collision as the masses changed? 4. Define the term momentum. 5. Which object has greater momentum, a butterfly traveling at 16 km/h or an eagle traveling at the same speed? 6. How does the transfer of momentum occur? 7. Use momentum to describe what would happen if a skaterboarder was hit by a car.
 * Questions:**
 * A car rear ending another car could be a possible real-life collision that is represented by smaller carts**
 * We changed the masses of each cart and applied different amounts of force each time. This helped us because we had more variables to deal with causing our guess to be more and more accurate**
 * The collisions varied as the masses changed. See chart above.**
 * Momentum is the quantity of motion of a moving body that is measured as a product of its mass and velocity**
 * An eagle traveling at the same speed because mass plays as a factor.**
 * The transfer of momentum occurs when the moving cart strikes the stationary cart. The stationary cart moves away at a certain speed, because the first automobile loses some of its momentum and transfers it to the stationary cart.**
 * Since a car has a much bigger mass than a skateboarder, it is also going to have a larger momentum. Since the momentum of the car is bigger when it collides with the skateboarder the skateboarder will have a more drastic injury since the momentum of the car gets transfered to the skateboarder which will make the skateboarder most likely fly into the air.**

Conclusion: **If a heavy truck and a small sports car had a head-on collision the truck would continue to move even after it hit the sports car. The sports car would ricochet off the truck and fly backwards very, very far. A cause of experimental error could be not accurately measuring the masses of the carts. To improve this lab I would measure each cart and mass individually and measure distance traveled by each cart every time to make it more accurate.**

SECTION 6:
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). 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)** || Initial momentum of bullet cart || Final momentum of the combined carts ||
 * .505 || .489 || .45 || 0 || .994 ||> .19 || .23 kg m/s || .19 ||
 * .755 || .489 || .47 || 0 || 1.244 ||> .25 || .35 kg m/s || .31 ||
 * .505 || .739 || .41 || 0 || 1.244 ||> .20 || .21 kg m/s || .24 ||
 * 1.005 || .489 || .36 || 0 || 1.494 ||> .21 || .36 kg m/s || .31 ||
 * .505 || .989 || .55 || 0 || 1.494 ||> .17 || .28 kg m/s || .25 ||
 * 1.255 || .489 || .41 || 0 || 1.744 ||> .27 || .51 kg m/s || .47 ||


 * 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
 * 2) Example trial 1: .505kg(.45m/s)= .23 kg m/s
 * 3) Find the initial momentum of the target cart for each trial.
 * 4) Find the sum of the initial momenta of the two carts for each trial.
 * 5) Find the final momentum of the combined carts for each trial.
 * 6) Example Trial 1: .994kg(.19m/s)=.19 kg m/s

** *Read the Physics Talk p312 - 315 before answering the following questions. * ** 1. Compare the initial momenta (calc 3) to the final momentum (calc 4). (Allow for minor variations due to uncertainties of measurement.) 2. List the 6 types of collisions (top of page 312) and a brief description. 3. Which types of collisions are definitely inelastic? How do you know? 4. Which types of collisions are definitely elastic? How do you know? 5. Define the law of conservation of momentum. 6. 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.
 * Questions:**
 * One moving object hits a stationary object and both stick together and move off at the same speed, two stationary objects explode by the release of a spring between them and move off in opposite directions, one moving object hits a stationary object and while the first object stops the second moves off, one moving object hits a stationary object and both move off at different speeds, two moving objects collide and both move at different speeds, and two moving objects collide while they stick together and move off at the same speed.**
 * the ones that have decrease of kinetic energy**

· 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? · 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:**