Chapter+3

[|Article] Toyota vehicles have been having a lot of recalls lately, dealing with accelerator pedals that could be trapped under the floor mat. Other recalls included fixing steering relay rods that could crack or break in some of their models. Since 2009, Toyota has recalled millions of vehicles worldwide, causing some shoppers to avoid Toyota completely. It is important for all of the parts of a car to work and work correctly for the amount of time that they are supposed to, so recalls don't happen. It is dangerous to drive a car that does not work and will most likely cause accidents. = = =Section 1= What do you think? We see a crash test with crash test dummies in the car. The circular things on the dummies help the people creating the tests in watching the movement of the objects. You can protect yourself from serious injury during an accident by taking all precautions possible to ensure not causing an accident to begin with. If you are in a vehicle, you can wear your seatbelt, sit where you are supposed to sit, and adjust the seating so that you are far enough away from the seat in front of you or the wheel. If you are doing a riding a bicycle or skating you should always wear a helmet, knee pads and elbow pads to protect your body from bruising or breaking if you fall.

Investigate toc 2a. **I was not surprised by my extent of knowledge because I rarely look at death rates of certain things** 3. (yes/no) || New Cars (1,2,3) ||
 * ** Safety features ** || Means of protection || Pre-1960 cars
 * seat belt || To stop people from moving out of their seats || no || 1, all ||
 * head restraints || Keep head stable || no || 1, all ||
 * front airbags || To stop the people from moving and hitting the steering wheel || no || 1, all ||
 * back up sensing system || To be able to see blind spots behind you || no || 3, few ||
 * front crumple zones || To redirect shock and absorb shock || no || 1,2, all, some ||
 * rear crumple zones || to redirect and absorb shock || no || 2, some ||
 * side-impact beams in doors || to absorb the impact || no || 1, all ||
 * shoulder belts for all seats || to keep upper body from moving in case of accident || no || 1, all ||
 * anti-lock braking systems (ABS) || stops breaks from locking || no || 2, some ||
 * tempered shatterproof glass || glass does not shatter || yes || 1, all ||
 * side airbags || to absorb impact || no || 1 ||
 * turn signals || to show the direction you are going || no || 1 ||
 * electronic stability control || helps resists rollovers || yes || 2, 3, some, few ||
 * energy-absorbing collapsible steering column || prevents chest trauma || no || 1, all ||

** Physics Talk ** Accidents will always happen no matter what. Certain systems in vehicles can help prevent accidents or help keep you safe in an accident. Governments and manufacturers of automobiles can work together to make vehicles safer. Pedestrians as well as passengers in the car are in danger of getting in an accident. Ralph Nadar wrote the book Unsafe at Any Speed highlighting the problems of not having seat belts in vehicles, having hard chrome dashboards and solid steering columns. Four wheel drive and anti-lock brakes are much safer in automobiles than those without these features.

** Checking Up ** 1. **Four wheel drive, seat belts, and solid steering columns** 2. **This increase in fatal 4WD crashes could be due to the growing number of kilometers traveled by 4WDs. Also, it could be due to the tendency of some drivers to increase speed under the impression that the safety feature will protect them**

Physics To Go 1. **Seatbelt (F,R,S,T), airbag (****F,R,S,T****), head restraints (****F,R,S****), back-up sensing system (R), anti-lock breaks (****F,R,S****), turn signals (****F,R****), side airbags (S), front/rear crumple zone (F/R), and side-impact beams (S).** 2. **Wear a helmet, knee pads, elbow pads, have a horn and learn hand-turn signals.** 3. **Wear a helmet, knee pads and elbow pads.** 4. **Wear a helmet, knee pads and elbow pads.**

What do you think now? To prevent yourself from being in an accident you should ensure that the vehicle or object you are using for transportation is the safest you can make it. You must supply yourself with the most adequate safety materials for your traveling. You must also always be alert and remember all of the past things we have learned from Active Physics. Wear a helmet, knee or elbow pads, or your seatbelt can help save you from a deathly accident.

=Section 2= What do you think? You see a man crashed into another car and the man that crashed has flown out of his car with his steering wheel in his hand. Both cars are almost completely crushed. The drive that crashed did not have a seatbelt on, but the other one did. If you had to design a seatbelt for a race car that could go 300 km/h it would be different than a regular seatbelt because it would have to be stronger, more heat resistant and much more flexible.

Physics Talk Newton's first law of motion is 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. There are three parts: 1, an object at rest stays at rest, 2, an object in motion stays in motion in a straight line with constant speed, and 3, this part says part one and two are only true when the net force on the object is 0. Inertia is the natural tendency of an object to remain at rest or to remain moving with constant speed in a straight line. A force is an interaction between two objects that can result in an acceleration of either or both objects. Pressure is force per area where the force is normal (perpendicular) to the surface; measured in N/m^2 (Newtons per meters square) or Pa (pascals).

Investigate 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?
 * Objectives:**


 * Hypothesis:** Respond to each of the above objectives fully.
 * A person that does not have a seatbelt on that is in a car accident has a much higher risk of getting hurt. They will most likely not have any control of what their body does when the accident occurs. Factors that affect the person's safety is where the accident happened, if they have a seatbelt on, if other passengers have their seat belts on, how big the car is that they are in/ other car that might have collided with, and the speed of the vehicle.**
 * Materials:** List any materials used and draw a labeled diagram of your set-up (alternatively, include a snapshot or video).
 * Ramp, cart, and a clay dummy**

Data and observations: Injury Height with no seatbelt: m


 * 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 ||

//** *Read the Physics Talk p268 - 271 before answering the following questions. * **// 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 seatbelts? 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 seatbelt 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 seatbelt 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.** 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. 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?)

Checking Up 1. **Newton's first law of motion states three different things: 1. an object at rest stays at rest, 2. an object in motion stays in motion in a straight line with constant speed, 3. parts one and two are only true when the net force on the object is 0. All together it states an object at rest stays in rest and an object in motion will stay in motion in a straight line with constant speed unless acted upon by a net, external force.** 2. **Because their motions will stop until they are acted upon by a force.** 3. **First collision- an automobile strikes a pole and the pole exerts the force that brings the automobile at rest. Second collision- when an automobile stops, the body keeps moving until the structure of the automobile exerts the force that brings the body at rest. Third collision- the body stops but the brain, heart and other organs keep moving until the body wall exerts the force that brings them to rest.** 4. **Inertia states that an object in motion will stay in motion and an object at rest will stay at rest. Unless someone pushes, pulls, kicks or disturbs the object in some way, it will stay in the state that it is in.** 5. **There is more mass to stop a big amount of mass.**

= **Section 3** = Hypothesis: A**n air bag protects you from an accident by blocking the driver or passenger's body from hitting the windshield, dashboard or steering wheel. It exerts a smaller amount of force than the rest of those three objects would, causing there to be a smaller blow to the body.**

Materials: **Egg, ruler, scale, and ziplock bag**

1. **Length: 6.2 cm Mass: .05763 kg** 5. **At 32 cm our egg was smashed and the yolk leaked out. The final height of our damaged egg is 2.6 cm** 7. **Length: 5 cm Mass: .06039 kg**
 * // 6. Fill a bowl with flour and place the bowl inside of the box lid. //**
 * // 7. Measure the length of your egg #2. Measure the mass of your egg. Record this information. //**
 * // 8. Drop the egg from the smash height (Step 5). 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. //**


 * **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 ||

> The egg represents the person in the car. The table represents the collision. The flour represents the air bag > **2. Define Kinetic energy and work** > 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. > **3. What factors determine an object's kinetic energy?** > 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. > **5. How does the force needed to stop a moving object depend on the distance the force acts?** > The object stopping the moving object is work. The less the distance, the greater the force. > **6. What difference does a soft landing area make on a passenger during a collision?** > 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. > **7. How does a cushion reduce the force needed to stop a passenger?** > 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 > **8. What does the law of conservation of energy have to do with this?** > 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.
 * 1) **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?**

Conclusion: ** · 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. · 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?) ** USE THE RUBRIC TO MAKE SURE YOU HAVE INCLUDED ALL REQUIREMENTS!

=Section 5=


 * **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.**

1) The momentum on the stopped vehicle will be greater because the vehicle has a larger velocity 4) They prefer the heavier linemen because the will affect other teams players more because their mass is larger. 5) The speed that each vehicle is going. 6) The vehicle would have to be stopped, with no velocity.
 * Physics To Go**:

=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 || ** *Read the Physics Talk p312 - 315 before answering the following questions. * **
 * .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 ||** ||  ||   ||   ||   ||   ||
 * 1) Find the initial momentum of the bullet cart for each trial
 * 2) Example trial 1: .505kg(.45m/s)= .23 kg m/s
 * 1) Find the initial momentum of the target cart for each trial.
 * 2) Find the sum of the initial momenta of the two carts for each trial.
 * 3) Find the final momentum of the combined carts for each trial.
 * 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;">Example Trial 1: .994kg(.19m/s)=.19 kg m/s

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**
 * The ones that are elastic have equal kinetic energy at the end**
 * The law of conservation of momentum states that momentum can neither be created nor destroyed, only transfered**
 * When the cue balls hits 15 pool balls in the middle of the table one ball is directly hit and it passes the momentum to the rest of the balls, causing all of them to move.**

· 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:**

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