Ch+3+Sec+2+KirnumB

=Section 2 =

What do you see? I see someone flying over their car and the car that they hit into because they weren't wearing their seatbelt

What do you think? A car that travels much faster would need to have a stronger seat belt because it needs to keep you from flying forward.

Physics talk Seat belts and Newton's First Law of Motion
 * Newton's first law of motion=inertia
 * When a car hits a pole
 * First collision: car hits the pole. The pole exerts the force that brings the car to rest
 * Second collision: the car stops but the body keeps moving. The structure of the car gives the force that brings the body to rest
 * Third Collision: the body stops, but the heart, the brain, and other organs keep moving
 * Force: Interaction between two objects that can result in an acceleration of either or both objects
 * Pressure: force per area where the force is normal to the surface; measured in N/m^2

Checking up
 * 1) Newton's 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
 * 2) <span style="font-family: Georgia,serif;">The driver in a car crash remains in a state of motion when the car stops suddenly beaus their bodies and organs are moving
 * 3) <span style="font-family: Georgia,serif;">Newtons first law and the three collisions: you body remains in motion because you are already in motion. It takes the seat belt to bring your body back to rest
 * 4) <span style="font-family: Georgia,serif;">Inertia: the natural tendency to remain at rest or to remain moving with constant speed in a straight line.
 * 5) <span style="font-family: Georgia,serif;">A broad band of material work better as a seat belt than a thin wire because it spreads out where it is slowing down your body.

<span style="font-family: Georgia,serif;">Investigate
<span style="font-family: Georgia,serif;">Objectives:
 * <span style="font-family: Georgia,serif;">What happens to a passenger involved in a car accident without and with a seatbelt?
 * <span style="font-family: Georgia,serif;">**If someone isn't wearing a seat belt, they will be thrown from the car.**
 * <span style="font-family: Georgia,serif;">What factors affect the passenger’s safety after a collision?
 * <span style="font-family: Georgia,serif;">**The speed at which they are traveling, weather or not they are buckled in and how hard they crash.**
 * <span style="font-family: Georgia,serif;">How would a seat belt for a race car be different from one available on a regular car?
 * <span style="font-family: Georgia,serif;">**In a race car, the seat belt must me must stronger because it needs to take care of your body at a much faster speed.**

<span style="font-family: Georgia,serif;">Hypothesis: Respond to each of the above objectives fully.
 * **Without a seat belt, a person will be thrown from a moving vehicle when it is in an accident**

<span style="font-family: Georgia,serif;"> Materials: List any materials used and draw a labeled diagram of your set-up (alternatively, include a snapshot or video).


 * **Clay**
 * **Ramp**
 * **Books**
 * **String**

Diagram

Procedure:


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

<span style="font-family: Georgia,serif;">Data and observations: <span style="font-family: Georgia,serif;"> Injury Height with no seatbelt: **.2** meters

is so small so it puts too much pressure in small area which digs into his body. || as a result of the narrow wire. When the cart plunged forward, he moved forward as well, pushing against his wire restraint. We observed lacerations to his shoulder and legs. ||  || the slant, he was in good condition and the ribbon was a decently sturdy seatbelt. After released down the slant the seatbelt restricted the person from falling out of the car. The damage wasn't very severe, he might have went through the windshield. Only a broken arm and maybe some injuries on the back/neck. Overall the seatbelt protected the clay person from death but no serious injuries. ||  ||   || || <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;">The clay model was sent down the incline/ramp with a seat-belt made out of tape. The tape was wrapped around his waist and than pulled over his shoulder. The seat-belt allowed the clay model to go down the incline without ending up out of the cart and with significant injuries. The clay model was still held in by the seat-belt by the end of the trial, so in all the tape seat belt worked. ||
 * <span style="font-family: Georgia,serif;">Type of Seatbelt || <span style="font-family: Georgia,serif;">Before Picture || <span style="font-family: Georgia,serif;">After Picture || <span style="font-family: Georgia,serif;">Description and Observations ||  ||
 * <span style="font-family: Georgia,serif;">Thread || [[image:activephysics-pvrhsd:Photo_293.jpg width="259" height="197" caption="Photo_293.jpg"]] || [[image:activephysics-pvrhsd:Photo_296.jpg width="251" height="192" caption="Photo_296.jpg"]] |||| The seatbelt holds him but the thread
 * <span style="font-family: Georgia,serif;">Wire || [[image:activephysics-pvrhsd:Photo_11.jpg width="286" height="212" caption="Photo_11.jpg"]] || [[image:activephysics-pvrhsd:Photo_12.jpg width="285" height="211" caption="Photo_12.jpg"]] || The clay passenger suffered cuts
 * <span style="font-family: Georgia,serif;">String || [[image:activephysics-pvrhsd:beforeclayman!.jpg width="256" height="192" caption="beforeclayman!.jpg"]] || [[image:activephysics-pvrhsd:afterclaymannn.jpg width="256" height="192" caption="afterclaymannn.jpg"]] || The clay man fell forward but no injuries but he was not thrown from the car like he was without being thrown from the car ||  ||   ||
 * <span style="font-family: Georgia,serif;">Yarn || [[image:activephysics-pvrhsd:Photo_on_2011-01-31_at_14.36.jpg width="300" height="228" caption="Photo_on_2011-01-31_at_14.36.jpg"]] || [[image:activephysics-pvrhsd:Photo_on_2011-01-31_at_14.37.jpg width="309" height="235" caption="Photo_on_2011-01-31_at_14.37.jpg"]] || The little clay man was sent flying down the incline with a two-point seatbelt made of yarn around his waist and across his body and shoudler, and crashed into the end, without significant injury. No cuts could be seen from the force of the yarn on the man and no body parts were missing or out of place. The cart hit the end of the track and the little clay man did not move sitting in place where I had placed him on the cart. ||  ||   ||
 * <span style="font-family: Georgia,serif;">Ribbon || [[image:activephysics-pvrhsd:before.png width="191" height="237" caption="before.png"]] || [[image:activephysics-pvrhsd:after.png width="325" height="147" caption="after.png"]] || Before we let our clay person go down
 * <span style="font-family: Georgia,serif;">Ribbon || [[image:activephysics-pvrhsd:before.png width="191" height="237" caption="before.png"]] || [[image:activephysics-pvrhsd:after.png width="325" height="147" caption="after.png"]] || Before we let our clay person go down
 * <span style="font-family: Georgia,serif;">1-in masking || [[image:activephysics-pvrhsd:tapeseatbeltan.jpg width="338" height="221" caption="tapeseatbeltan.jpg"]] || [[image:activephysics-pvrhsd:afteranseat.jpg width="338" height="221" caption="afteranseat.jpg"]] || <span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px; height: 600px; line-height: 1.5; min-height: 600px; overflow-x: auto; padding-bottom: 2em; width: 820px;">

<span style="font-family: Georgia,serif;">*Read the Physics Talk p268 - 271 before answering the following questions. * <span style="font-family: Georgia,serif;"> Questions:
 * 1) <span style="font-family: Georgia,serif;">Define the terms: inertia, force and pressure.
 * 2) <span style="font-family: Georgia,serif;">**inertia: the tendency an object has to remain at rest or to remain moving in a constant speed in a straight line**
 * 3) <span style="font-family: Georgia,serif;">**force: an interaction between two objects that results in acceleration**
 * 4) <span style="font-family: Georgia,serif;">**pressure: force per area where the force is normal to the surface (N/m^2)**
 * 5) <span style="font-family: Georgia,serif;">In the collision, the car stops abruptly. What happens to the “passenger”?
 * 6) <span style="font-family: Georgia,serif;">The passenger wants to keep moving straight
 * 7) <span style="font-family: Georgia,serif;">What parts of your passenger were in greatest danger (most damaged)?
 * 8) <span style="font-family: Georgia,serif;">**Organs**
 * 9) <span style="font-family: Georgia,serif;">What does Newton’s first law have to do with this?
 * 10) <span style="font-family: Georgia,serif;">**They want to keep moving and the body forces them to stop**
 * 11) <span style="font-family: Georgia,serif;">What materials were most effective as seatbelts? Why?
 * 12) <span style="font-family: Georgia,serif;">**An object with a larger surface area to spread the force needed to slow the body down. If it wasn't thick, it would dig into the person.**
 * 13) <span style="font-family: Georgia,serif;">Use Newton's first law of motion to describe the three collisions.
 * 14) **Collision 1: The pole is at rest and will remain at rest. It has to exert an external force on the object in motion, car, to bring it to rest**
 * 15) **Collision 2: The body wants to remain in motion and needs an external force to bring it to rest**
 * 16) **Collision 3: The body, an external force, brings the organs to rest**.
 * 17) <span style="font-family: Georgia,serif;">Why does a broad band of material work better as a seatbelt than a narrow wire?
 * 18) <span style="font-family: Georgia,serif;">**A broad band spreads the pressure used to slow down your body. A narrow wire applies too much force to one area.**

<span style="font-family: Georgia,serif;">Conclusion: <span style="font-family: Georgia,serif;"> · Using Newton's First law of Motion, explain why a seat belt is an important safety feature in a vehicle. What factors affect the effectiveness of a seatbelt? What would you need to consider when designing a seatbelt for a race car? Use specific observations from this investigation to support your answers to these questions. <span style="font-family: Georgia,serif;"> · Explain at least 1 cause of experimental error. Be sure you describe a specific reason. <span style="font-family: Georgia,serif;"> · How would you improve the results of this lab? (In other words, what would you change about the materials or procedure to eliminate or reduce the experimental error you describe above?)
 * <span style="font-family: Georgia,serif;">**Seat belts are very important because they keep your body from flying out of a car in an accident. If the seat belt is too thin it could end up hurting you instead of helping. You need to consider the speed of the car when making its seat belt. The faster it goes, the more pressure will be needed to slow the person down. In a race car, the seat belts would have to be much larger to spread the pressure.**
 * <span style="font-family: Georgia,serif;">**You could create an error by thinking that an injury from getting hit my the cart was due to the clay person flying from the cart.**
 * **I would make sure that the clay people are very flat so it is much easier to see the results of the accident.**