Chapter+3

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Chapter 3 toc

Section 1
In this picture I see a car that is crashing and the front of the car is smashed in. The people in the car are leaned forward. A way to protect yourself from an injury in an accident is by creating some sort of resistance against your motion to keep you in place. A way of doing this can be an airbag, seatbelt, and etc.
 * What do you see/think?**

1. Quia 2a. The score I received after taking the Quia was a 13 out of 15. I was pretty surprised with my knowledge, due to the fact I mysteriously was familiar with he topic. The label I received for achieving a score of 13 was an Assistant Analyst
 * Investigation**

(yes/no) || New Cars (1,2,3) ||
 * ** Safety features ** || Means of protection || Pre-1960 cars
 * seat belts || Restricts passenger from flying forward. || No || 1 ||
 * head restraints || Prevents whiplash. || No || 1 ||
 * front airbags || Prevents from flying out the car. || No || 1 ||
 * back up sensing system || allows to see blind spot while backing up || No || 3 ||
 * front crumple zones || increase collision distance reducing impact || No || 1,2 ||
 * rear crumple zones || increase collision distance reducing impact || No || 2 ||
 * side-impact beams in doors || resist side penetration || No || 2 ||
 * shoulder belts for all seats || keeps passenger in seat || No || 1 ||
 * anti-lock braking systems (ABS) || helps prevent skids || No || 2 ||
 * tempered shatterproof glass || prevents cuts || Yes || 1 ||
 * side airbags || protects head/torso in side collisions || No || 2 ||
 * turn signals || Lets other drivers know what direction you are going next. || Yes || 1 ||
 * electronic stability control || helps resist rollovers || No || 2,3 ||
 * energy-absorbing collapsible steering column || prevents chest trauma || No || 1 ||

- A car with many safety features can reduce the risk of injury in an accident - Ralph Nader wrote //Unsafe at Any Speed// //-// It addresses the importance of wearing a seat belt and points out the flaws of many drivers - Some driers driver faster because they think the seat belt will completely prevent injury - Car manufacturers since then have made cars safer
 * Physics Talk**

1. They made cars safer by putting in seat belts, head restraints, and solid steering columns. 2. The people think they are safer so they drive faster and take more risks.
 * Checking Up**


 * PTG**

1. seat belts- F and R 2. head restraints- F and R  3. front airbags- F  4. backing up system- R  5. front crumple zones- F  6. rear crumple zones- R  7. side impact beams- S  8. shoulder belts- F and R  9. anti-lock braking systems- F  10. tempered shatter proof glasses- F and R and S 11. side airbags- S 12. turn signals- R 13. electronic stability control- T 14. energy- absorbing collapsible steering column- F

2. Bicycle: Helmet, Brakes, Elbow and Knee Pads 3. In Line Skating: Helmet and Elbow/Knee Pads 4. Skateboards: Helmet and Elbow/Knee Pads

The way to protect yourself from serious injury in an accident is by mainly wearing a seat belt. Also, you should make sure your car has all the available safety features. Such as front and side airbags, head rest, reinforcement panels, and etc. All of these safety features can reduce the risk of serious injury.
 * What do you think now?**

**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?
 * A car accident without wearing a seatbelt, the passenger can actually fly through the windshield of a car. When wearing a seatbelt, this can be avoided and there may not be any harm.
 * What factors affect the passenger’s safety after a collision?
 * Seat belts, airbag, head rest.
 * How would a seat belt for a race car be different from one available on a regular car?
 * A seat belt for a race car would need more support in order to have the passenger to remain safe in a high speed collision.


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


 * 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.
 * 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: Injury Height with no seatbelt: .085 m


 * Physics Talk**


 * 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?
 * 1) Why does a broad band of material work better as a seatbelt than a narrow wire?

> 1. Inertia is the tendency of an object to keep in straight line motion. Force is the interaction between two objects, in which force equals mass times acceleration. Pressure is the force of an object per area which is measured in N/m^2 or just Pa. > 2. Due to inertia, the passenger will remain moving in the speed and direction of the car. > 3. The head of our passenger was in the most danger because every time he crashed, his head would fly forward first. > 4. This has to do with Newtons First Law because the passenger will remain in a straight line motion until an unbalanced for acts upon it. > 5. The most effective seat belt was most likely ribbon because it is a strong material that allows for the passenger's straight line motion to be reduced in the crash. > 6. Newtons First Law of motion describes the collisions because the seat belt is the unbalanced force that is going to stop the object going in constant motion. > 7. A broader band reduces the pressure of the passenger in the event of a collision. The narrow wire increases pressure and makes the passenger fly forward. > > > **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. > · 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?) > //In order to reduce experimental error in this lab, it may be better or placing the cart on the top of the incline and then put something in front of the cart so it does not fall down yet. Maybe put a ruler in front to stop it, then when ready remove the ruler so it falls at the normal pace, rather than getting maybe a slight push.//
 * //When designing a seat belt, Newton's First Law of Motion must be taken into consideration. This states that an object in motion, the passenger, will stay in motion until an opposite force acts upon it, the seat belt. The seat belt in a car is the opposite force acting on the passenger. When a seat belt is designed, it must be able to stop the passenger from flying forward. The seat belt must also be wide so that all of the force is spread over a greater area, reducing the pressure on the passenger.//
 * //One cause of experimental error in this lab may have been giving the cart a little bit of a push at the start of the incline, increasing the speed of the cart. This could cause the seat belt going from safe, to unsafe.//

**Section 3**
Investigate X3: Energy and Air Bags

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

**Hypothesis:** Respond to the objective fully. //An airbag protects you during an accident by absorbing the blow of the passenger.// **Materials:** List any materials used and draw a labeled diagram of your set-up (alternatively, include a snapshot or video).

**Procedure:**

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

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


 * **Egg #** || **Drop Height** || **Cracked or Smashed?** || **Description and Observations** || **Mass (kg)** || **Height of Egg After Drop (m)** || **Total Damage or Sinkage (m)** ||
 * 1 || 2 cm. || The egg cracked. || The egg slightly cracked on the point of impact. || 0.055 || 0.060 || 0 ||
 * 1 || 4 cm. || The egg cracked. || The egg had a more severe crack at the point of impact. || 0.055 || 0.060 || 0 ||
 * 1 || 6 cm || The egg CRACKED || The egg became indented. || 0.055 || 0.058 || 0.002 ||
 * 1 || 8 cm. || THE EGG cracked.... || More indentation and cracks. || 0.055 || 0.056 || 0.004 ||
 * 1 || 10 cm || The egg cracked || The egg is in a cracked state. Most of the egg is cracked. || 0.055 || 0.056 || 0.004 ||
 * 1 || 12 cm || Cracked || The egg is still cracked and white oozed out || 0.055 || 0.055 || 0.005 ||
 * 1 || 14 cm || Severely cracked. || Cracked to the point of major oozing || 0.055 || 0.050 || 0.010 ||
 * 1 || 16 cm || Smashed || The yolk is completely out. || 0.055 || 0.045 || 0.015 ||
 * 1 Pt. 2 || 16 cm || No cracks at all. || The egg sank about 0.016 m. || 0.0564 || 0.040 || 0.016 ||
 * 1 Pt. 2 || 20 cm || No cracks at all. || The egg sank about 0.021 m. || 0.0564 || 0.035 || 0.021 ||
 * 1 Pt. 2 || 24 cm || No cracks at all. || The egg sank about 0.024 m || 0.0564 || 0.032 || 0.024 ||
 * 1 Pt. 2 || 28 cm || No cracks at all. || The egg sank about 0.025 m. || 0.0564 || 0.031 || 0.025 ||
 * 1 Pt. 2 || 2 m || No cracks || The egg sank about 0.028 m || 0.0564 || 0.028 || 0.028 ||
 * 1 Pt. 2 || 2.5 m || The egg finally cracked from an outrageous height. || The egg had cracks surrounding it. It exploded. It sank down right to the end of the plate about 0.030 m. || 0.0564 || 0.026 || 0.030 ||


 * 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?
 * Part I:**
 * = Trial ||= GPE (mgh) ||= Answer (Joules) ||
 * = 1 ||= (.055g)(9.8m/s sq.)(2cm) ||= 10.78 ||
 * = 2 ||= (.055g)(9.8m/s sq.)(4cm) ||= 21.56 ||
 * = 3 ||= (.055g)(9.8m/s sq.)(6cm) ||= 32.34 ||
 * = 4 ||= (.055g)(9.8m/s sq.)(8cm) ||= 43.12 ||
 * = 5 ||= (.055g)(9.8m/s sq.)(10cm) ||= 53.90 ||
 * = 6 ||= (.055g)(9.8m/s sq.)(12cm) ||= 64.68 ||
 * = 7 ||= (.055g)(9.8m/s sq.)(14cm) ||= 75.46 ||
 * = 8 ||= (.055g)(9.8m/s sq.)(16cm) ||= 86.24 ||


 * = **Part II:**

Trial ||= GPE (mgh) ||= Answer (Joules) ||
 * = 1 ||= (.564g)(9.8 m/s sq.)(16cm) ||= 88.435 ||
 * = 2 ||= (.564g)(9.8 m/s sq.)(20cm) ||= 110.544 ||
 * = 3 ||= (.564g)(9.8 m/s sq.)(24cm) ||= 132.653 ||
 * = 4 ||= (.564g)(9.8 m/s sq.)(28cm) ||= 154.762 ||
 * = 5 ||= (.564g)(9.8 m/s sq.)(200cm) ||= 1,105.44 ||
 * = 6 ||= (.564g)(9.8 m/s sq.)(250cm) ||= 1,381.80 ||


 * How much work is done in each trial?


 * Part I:**
 * = Trial ||= Work (F * d) ||= Answer (Joules) ||
 * = 1 ||= (.539N)(2cm) ||= 1.078 ||
 * = 2 ||= (.539N)(4cm) ||= 2.156 ||
 * = 3 ||= (.539N)(6cm) ||= 3.234 ||
 * = 4 ||= (.539N)(8cm) ||= 4.312 ||
 * = 5 ||= (.539N)(10cm) ||= 5.390 ||
 * = 6 ||= (.539N)(12cm) ||= 6.468 ||
 * = 7 ||= (.539N)(14cm) ||= 7.546 ||
 * = 8 ||= (.539N)(16cm) ||= 8.624 ||


 * Part II:**
 * Trial || Work (F * d) || Answer (Joules) ||
 * 1 || (.553)(16cm) || 8.848 ||
 * 2 || (.553N)(20cm) || 11.06 ||
 * 3 || (.553N)(24cm) || 13.27 ||
 * 4 || (.553N)(28cm) || 15.48 ||
 * 5 || (.553N)(200cm) || 110.60 ||
 * 6 || (.553N)(250cm) || 138.25 ||


 * How much force was used to stop the egg in each case of steps 5, 8 and 9.
 * The Force on the Egg was 0 because it was dropped and not thrown.


 * 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 rice represent?
 * 2) Define the terms: Kinetic Energy and Work.
 * 3) What factors determine an object's kinetic energy?
 * 4) When work is done on an object, what is the effect on the 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?

1. The egg represents the person, the table represents the energy involved in the collision, and the flour represents an airbag. 2. Kinetic Energy is the amount of energy of an object in motion. Work is the amount of energy required to stop an object with a certain force and distance. 3. The factors that determine an object's KE is mass and velocity. 4. The objects KE decreases all the way to zero. 5. It depends on it because a greater distance represents a smaller force and vice versa. 6. It provides a smaller force over a larger distance, making it act as a glove and safer for a passenger. 7. A cushion reduces the force needed to stop a passenger because it is a smaller force over a larger distance. 8. The Law of Conservation of Energy has to do with this because all of the KE is converted to W when it stops.

· 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.
 * Conclusion:**

//An Airbag can protect you from an accident due to the Law of Conservation of Energy. The KE is converted into W from the airbag. The airbag provides a smaller force over a larger distance which increases the safety of the passenger. In every stage of an accident, the total amount of energy is the same.// · Explain at least 1 cause of experimental error. Be sure you describe a specific reason.

//One cause of experimental error in the lab may have been not measuring the height correctly. This meaning the egg may not have been dropped at the exact height we wanted. This would throw off the calculations of Work and KE.// · 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?)

//In order to improve these results, it would be more sufficient before dropping the egg, to get to eye level of the egg and ruler to make sure it is at the desired height. For example, if the desired height of the egg is 16 cm., you should get eye level to 16 cm and make sure the bottom of the egg is at exactly 16 cm.//

Section 6
** Investigate X6: Momentum and Inelastic Collisions **

Objective: What physics principles do the traffic-accident investigators use to "reconstruct" the accident?
 * In order to reconstruct the accident, they take velocity and mass into account to find the vehicle's total momentum.**

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

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


 * **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)** ||
 * .502 || .494 || .57 || 0 || .996 || .27 ||
 * 1.002 || .494 || .47 || 0 || 1.496 || .25 ||
 * .502 || .994 || .56 || 0 || 1.496 || .19 ||
 * 1.002 || .994 || .36 || 0 || 1.996 || .14 ||
 * 1.502 || .494 || .43 || 0 || 1.996 || .24 ||

>> 1. p = (.501)(.85)= 0.426 km(m/s) >> 2. p = (.726)(.84)=0.609 kg(m/s) >> 3. p = (1)(.65)=0.65 kg(m/s) >> 4. p = (1.25)(.79)=0.988 kg(m/s) >> 5. p = (1.5)(.75)= 1.125 kg(m/s) >> 6. p = (1)(.76)= .76 kg(m/s) >> 1. p = (.499)(0)= 0 kg(m/s) >> 2. p = (.499)(0)= 0 kg(m/s) >> 3. p = (.499)(0)=0 kg(m/s) >> 4. p = (.499)(0)= 0 kg(m/s) >> 5. p = 1(0)=0 kg(m/s) >> 6. p = 2(0)=0 kg(m/s) >> 2. .609+0= .609 kg(m/s) >> 3. .65+0= .65 kg(m/s) >> 4. .988+0= .988 kg(m/s) >> 5. 1.125+0= 1.125 kg(m/s) >> 6. .76+0= .76 kg(m/s) >> 1. p= (1.009)(.42)= 0.424 kg(m/s) >> 2. p= (1.225)(.49)= 0.6002 kg(m/s) >> 3. p= (1.499)(.5)= 0.7495 kg(m/s) >> 4. p= (1.749)(.61)= 1.0669 kg(m/s) >> 5. p= (2.5)(.45)= 1.125 kg(m/s) >> 6. p= (3)(.31)= 0.93 kg(m/s)
 * 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) p= mv
 * 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;"><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;">Find the initial momentum of the target cart for each trial.
 * 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;"><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;">p=mv
 * 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;"><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;">Find the sum of the initial momenta of the two carts for each trial.
 * 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;"><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;">p = mv
 * 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;"><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;">1. 0.426+0= .426 kg(m/s)
 * 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;"><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;">Find the final momentum of the combined carts for each trial.
 * 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;"><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;">p=mv


 * Questions:**
 * 1) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">Compare the initial momenta (calc 3) to the final momentum (calc 4). (Allow for minor variations due to uncertainties of measurement.)
 * 2) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">List the 6 types of collisions (top of page 312) and a brief description.
 * 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;">Which types of collisions are definitely inelastic? How do you know?
 * 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;">Which types of collisions are definitely elastic? How do you know?
 * 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;">Define the law of conservation of momentum.
 * 6) <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">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.

· 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:**

Section 7
<span style="font-size: 1.3em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;">****Investigate 7: Impulse and the Crumple Zone****

// Objective: A crumple zone is part of the body of a car that compresses during an impact. It absorbs the energy of the collision and lessens the force on the passengers. //
 * <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 are some of the factors that car designers and engineers must consider when designing a crumple zone as a safety feature?
 * <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;">A factor that designers must consider is that the crumple zone of the car is large enough to not reach the passenger in any accident.
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;"><span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif;">What enables a passenger to survive a collision?
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">A seatbelt, large crumble zone, and small force help a passenger survive a collision.
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;"><span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif;">What does a Force vs. Time graph look like for a collision?
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">A force vs time graph shows the force increase at a maximum during a collision.
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;"><span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif;">What would the Force vs. Time graph look like if the collision was more safe?
 * <span style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0.5em; padding-bottom: 0px; padding-left: 3em; padding-right: 0px; padding-top: 0px;">If the collision was safe, the maximum of the force vs time graph would be small.

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

//Procedure:// // 1. On the floor, place a ramp on a stand so that one end is raised 10-cm and the other end is 20 cm from the wall. // // 2. Place a block in the cart and attach a 2-cm piece of masking tape to the front of the block and down onto the cart. Place the cart at the top of the ramp and release it. Record your observations. // // 3. Design a crumple zone to protect the block from tipping over. You can use only the following materials: one sheet of paper, 30-cm tape, 2 rubber bands, and 30-cm of string. Record your design(s) and the changes you make to it in a data table. You may want to use the available technology (still pictures and video) to supplement your written descriptions. // // 4. Measure the mass of your cart with apparatus attached. // // 5. Once you have a functional design that you are happy with, you will bring it to the front of the room to test. You will allow your cart to crash into a force sensor in order to generate a force vs. time graph, while a motion detector will measure the speed of the cart. // // 6. Click the ∑ button to get the area of the F-t Graph. Click the smart tool to get the velocity of the cart before and after the collision. // // 7. Repeat 3 times. //


 * Data and observations:** Add more columns/row as needed.
 * **Trial** || **Mass of Cart with apparatus(kg)** || **Speed of Cart** before collision(m/s) || **Speed of cart after collision (m/s)** || **Area on F-t graph (Ns)** || **Change in momentum (kgm/s)** || **Impulse (Ns)** ||
 * No Crumple Zone (teacher) ||  ||   ||   ||   ||   ||   ||
 * #1 with CZ ||  ||   ||   ||   ||   ||   ||
 * #2 with CZ ||  ||   ||   ||   ||   ||   ||
 * #3 with CZ ||  ||   ||   ||   ||   ||   ||

**Calculations:** Show equation(s), numbers plugged in, and answer with correct units. Add columns in your data table to include these results. 1. Calculate the change in momentum for your cart. 2. Impulse is equal to the area of the F-t graph. What is the impulse experienced by your cart?

***Read the Physics Talk p324 - 329 before answering the following questions.** *

1. Define the following terms: velocity, acceleration, Newton’s second law of motion, and momentum, impulse. 2. What is a crumple zone? 3. Why is it safer to collide with a soft cushion than a hard surface? 4. What is the relationship between impulse and change in momentum? 5. How is the impulse-momentum relationship related to Newton’s second law? 6. What were the key features of your crumple zone and why were they important? 7. What happened to the area of the Force-time graph as we increased the speed of the cart? 8. What happened to the area of the Force-time graph when the collision was inelastic vs. elastic?
 * Questions:**

**Conclusion:** · What are some of the factors that car designers and engineers must consider when designing a crumple zone as a safety feature? Compare and contrast crumple zones and air bags. · 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?)