Chapter+One

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 * Chapter One : Driving the Roads**
 * Section One : Reaction time- Responding to road hazards**

9/7/11 __What do you see?__
 * orange and yellow cars in a two car pile-up
 * blue car speeding down road
 * blue car skidding to a stop
 * bendy road
 * broken glass under orange car
 * different license plates
 * blue car's back wheels are up

__What factors affect the time you need to react to an emergency situation?__ 9/8/11 __Investigate__ 1. a.) test one: .65 sec test two: .56 sec test three: .65 sec average reaction time= .62 sec
 * distractions (such as cellphones, reaching for something, talking)
 * drugs and alcohol consumption
 * speed
 * physical condition
 * weather
 * distance
 * driving experience

2. b.) test one: .55 test two: .53 test three: .45 average reaction time:.51

test one: .81 test two: .18 test three: .19 average reaction time: .39
 * //Method A: starting and stopping stopwatches//**

test one: 25 cm test two: 37 cm test three:17 cm average reaction time: 26.3 cm average time it took: .22 sec
 * //Method B: catching a ruler//**

9/9/11 1.) group one : .15, .18 average: .16 group two: .21, .19, .17 average: .19 my average: .23
 * Comparing methods of measuring reaction time:**

My groups average reaction time was .07-.04 slower than group one and group two.

a.) The reaction times vary because everyone reacts to things differently and age can also be a factor. b.) I think catching the meter stick was the most accurate because it requires more skill than seeing how fast you move your foot back and forth pedal to pedal.

2. group one: .26, .22 average: .24 group two: .2, .23, .32average: .25

9/12/11 1.) Reaction time with distractions: 23 cm 14 cm 94 cm 24 cm, 27 cm average: 36.4 cm average reaction time: .27 secs

a.) My reaction time including a distraction is slightly slower (.04) because I need to process the information before proceeding. b.) When doing different tasks while driving such as changing a cd or eating, reaction time would be slower because you are concentrating on the other task also, not full attention on the road.

2.) catching meter stick while changing a cd 40, 28, 55 average: 41 cm reaction time with distraction: .29 secs

a.) I have a slower reaction time while being distracted by changing a CD and dialing a phone number on the calculator because I am trying to do something else while still trying to catch the ruler on command. b.) Ten activities that can distract you while driving is:
 * 1) talking to passengers
 * 2) music
 * 3) being tired
 * 4) putting on make-up
 * 5) texting/ talking on the phone
 * 6) eating/drinking
 * 7) putting on/taking off a jacket
 * 8) having kids in the backseat
 * 9) switching radio stations
 * 10) looking at views off the road

checking up 1. Distractions slow down reaction time because you are not completely concentrated on what you are doing. You are not able to to fully focus on the road and something else at the same time. 2. Driving under the influence of alcohol or drugs is illegal because it alters your alertness which is needed for sudden emergency actions. 3. Other factors that affect reaction time are age, experience, and physical condition.
 * Physics Talk**

9/13/11 1. a.) b.)
 * Active Physics Plus**



c.) This graph is the exact same graph as the one on page 10.

1.) mom: 14 cm, .162 sec dad: 13 cm: .149 2.) I think there is a difference in the reaction times from family and from people in class. I think the difference is due to the fact that in class, we know what to expect from observing groups around us so we anticipate the ruler falling. 4.) I feel that both race car drives and someone driving in a school zone need equally fast reaction time due to speed and distractions. With the race car driver, they are driving extremely fast and have to worry about two things, passing the car in front of them and blocking the car in back of them from going past them. In a school zone, the speed is significantly lower, more around 5 mph compared to race speed of 200 mph, but there are more pedestrians and distractions to be more cautious. 5.) Alcohol, changing radio stations, or speaking on a cell phone slows down reaction time because they are distractions which make the person not as focused on the road. 6.) If one's reaction time is slow when driving, it can result in serious issues such as accidents. 7.) The insurance is more expensive for teenage drivers because they are new drivers and do not have as much experience. As the years go by with the kids having their licenses and not getting into accidents, the insurance price will decrease. 8.) Knowing your reaction time allows you to know how important it is to always be alert so you can avoid putting your life or other people's lives in danger.
 * Physics to go**

9/14/11 __Section two__ **What do you see?**
 * odd number doors, 103, 105, 107- moving in an ascending direction
 * boy with a clipboard and pen
 * notebook the floor
 * little girl following behind bigger kid walking
 * the hallway is labeled physics
 * measuring tape on the ground
 * the little girl and bigger boy are walking parallel to the measuring tape
 * boy with clipboard is taking down notes
 * girl observing from room 107
 * floor is dirty


 * What do you think? **
 * If one student measures 3 m and 10 m there must have been a mistake because that is a big difference in meters.
 * Interpreted it different, one was more precise.

2. a.) 33
 * Investagate**

3. a.) 41 cm

4. a.) 33x41= 1,353

5. a.) 866 cm b.) There are differences in measure due to the fact that people have different stride amounts and length of the strides and how precise someone is with their measurements. c.) A way to improve your measurements is to carefully mark the length with a pen so you can have more precise measurements.

6. a.) 2,318

7. a.) No, the measurements do not all agree. b.) I think the differences of the measurements is due to the fact that both groups were giving different distances. Also some groups results can vary due to sloppiness. c.) A way to improve measurements is to measure, then mark with a pencil, and continue. d.) If each group was given a long tape measure, I think that it comes along with obstacles such as where to start measuring from, which side to use, and how precise the reading is.I don't not think that each group would get the exact same value. e.) No, there will always be systematic errors.

8. a.) When measuring in the hallway, I had a systematic error because we did not start the tape measure at the right spot, we started the tape measure about around the 5 cm mark. b.) Our random errors came about because sometimes we flipped the meter stick not exactly where we should have, added a few cm or taken away a few cm each time.

9. a.) Reasonable, they must be muscular and heavy, around 220 and up b.) Unreasonable, 13 ft tall, is not normal, usually 6 feet tall c.) Unreasonable, 1440 mins is equivalent to 24 hours d.) Unreasonable, a poodle is light weight e.) Unreasobale, that is too big of a room for a classroom f.) Reasonable h.) In order to decide whether to stop and wait for the truck to cross or squeeze by depends on estimating how fast the truck is going and if there is enough room on the road to pass the truck. i.) Yes, The motor home is about 9-10 feet tall, and bikes around 3 feet tall, so that gives enough room to fit under the sign.

1.) Systematic errors can be fixed by calculations and random errors cannot. Systematic errors are usually formed when not using the measuring tool correctly. 2.) There will always be uncertainty in measurement because some tools are not made correctly, because people make systematic errors and random errors. 3.) They would need to be scattered throughout the object.
 * Physics Talk**

9/18/11 Reaction time of both sides of my family- the Iannello's vs. the Redicans
 * Side of family || Distance (cm) || Time (sec) ||
 * Iannello (uncle Scott) || 12 cm || .156sec ||
 * Iannello (cousin Jess) || 9 cm || .135 sec ||
 * Iannello (cousin Daniella) || 8 cm || .127 sec ||
 * Iannello (aunt Lisa) || 16 cm || .18 sec ||
 * Iannello (cousin Nick) || 19 cm || .196 sec ||
 * Redican (grandma) || 25 cm || .225 sec ||
 * Redican (uncle Chris) || 20 cm || .202 sec ||
 * Redican (cousin Ryan) || 17 cm || .186 sec ||
 * Redican (cousin Tori) || 14 cm || .169 sec ||
 * Redican (aunt Ann) || 24 cm || .221 sec ||

1.) (49.9 - 50.1 m) 20 cm range (49.99 - 50.01 m) 2 cm range (49.999 - 50.001 m)
 * Physics Plus**

2.) speed= distance/time speed=50m/25 sec =2m/s t=d/s t=2 cm/ 2 mpsec =.02 m/ 2meterspersec =.01 secs

3.) 60 cm /x= 150000 cm /900 sec = .36 s

.36 secs

4.) It is possible that the new record holder is actually slower than the previous record holder because not every swimming pool can measure to be exactly 50 m. Pools can be cm off and that length difference plays a huge role in times. Adding cm to the pool adds time to the swimmers race.

5.) Dear Olympic Commissioner, Time is significantly added to the swimmers race speed due to the size of the pool. Each Olympic games is in a new country or city and not every pool is exactly 50 meters long. There are small length differences that cause a big impact on time. In order to make things fair, every swimmer must swim the same exact distance as those swimmers in the past Olympic games. To fix this, measurements should be taken from every pool and compare the length of the pool to each other plus the time of each swimmer to each other.


 * What do you think now?**
 * No, the students did not make a mistake, it was either a systematic error or a random error.
 * No, it could have been a random error. It is advised to be as precise as can be when measuring

- This is a systematic error, it can be fixed because you know the difference between meters and yardsticks. - The jeweler does not know for sure that the gold is exactly 1 oz. It can just be an estimate - Most measurements have uncertainties, but all experiments require measurements.. it just gives you a good idea of what you're studying. We understand what tools were used, which environment, the average and all the conditions that add up to making mistakes. - Not estimating accurately leads to problems such as accidents.. if there is not enough space between your vehicle and other vehicles while driving, they can collide or skim sides.
 * Essential Questions**

1.) lengths length of laptop screen- 28.7 ( ruler) length of bulletin board- 1.231 cm (meter stick) height of lab table- 84.3 cm (meter stick) height of 23.7 oz water bottle- 25.4 cm (ruler) length of shelf- 41.8cm (ruler) b.) there are always uncertainties in measurements due to systematic and random errors. 2.) length of classroom: 20 strides.. width: 13 strides each stride about 41 cm 533 cm width 820 cm length size of room 2706 cm 3.) Agree- takes us half hour to 45 minutes to get ready before school disagree: length of shower.. I take a 10 minute shower, Jess takes a 4.) An oil tanker is supposed to hold 5,000,000 barrels of oil but it can be off by gallons. If each barrel costs $100 the possible value of the oil tankers oil can be from 5 billion dollars to 4 billion dollars. We do not know how accurate this measure is because this problem is not giving us enough information. 5.) The measures of the food are pretty accurate but not precise because of differences of scales 6.) Not reasonable, one liter serves about 4 people so two would serve about 8 people, three or 4 liters would be ideal. Yes, that is reasonable, from NY to Boston is about 3 hours, a full tank would be fine. 7.) A wrong measurement is a wrong measurement but the error is more prominent in a room rather than in miles due to size. 8.) You should drive about 60 mph. the passenger can time how long it takes in secs to get to each light post or a landmark and find the speed (speed= distance/t) 9.) In driving, it is sometimes a challenge to read the speedometer to find the exact speed. In a 30 mph zone and the driver is going 31 mph, that should not qualify for a ticket because it is only one mph over the limit. It is hard to keep your foot on the pedal at exactly the right speed. A ticket should only be addressed to those exceeding the speed limit by 10 and up mph.
 * Physics to go**

__section three__
 * What do you see?**
 * blue car in front of red and yellow car
 * yellow looks like it is connected to or hit into red car, red car looks connected or hit into blue car
 * the three cars^ are continuing to drive fast
 * cars going the opposite way are a safe distance from each other
 * on one side of the road, the rocks look the landmarks and on the other side, the yellow pole looks like it
 * cars on the highway
 * cars are going fast - bunnies ears and the grass are being blown by the wind


 * What do you think?**
 * a safe distance while driving vehicles is about 2 or 3 seconds from the car in front of you
 * a safe distance is about one or two lengths of a car or you can look at a landmark and count how many seconds it takes you to get there since the first car reached it, (2 second rule).. also a safe driving distance is one where you are confident that in case of emergency, you can stop the car quick enough to avoid an accident.


 * Investigate**
 * 1**



2a. 45mph

// b. the automobile is at a constant distance when driving at a constant speed. When the car goes slower, at 30 mph, there is less distance between the cars. At 45 mph the images further due to a higher speed. //

//c. I placed the images half the distance of the images at 30 mph.// //60 mph//

3.a. A is driving the slowest and C is driving the fastest. The more distance in between the images, the slower the car is traveling at. 3 b. Each car is traveling at a constant speed because the cars are equidistant from each other.

9/26/11 4. a. Graph of a person walking toward the motion detector at a normal speed.

b. Walking away at a normal speed.

c. Walking away and then towards it very slow speed.



d. Walking both directs at a fast speed.



e. When the person is walking toward the detector, there is a negative correlation and there is a positive correlation when walking away from the detector. Also, when the person is walking at an increased speed, the slope is increased compared to walking at slower speeds.

5. I predict that the graph will start out with a negative slope and then a positive slope

a.

b. My prediction was very accurate.

6 a.



b. If you forgot to label the two lines, you can determine which ones which due to the steepness of the slope or by the positive or negative correlation of the graph.

7. a. In trial 1, I walked 1.29 meters In trial 2, I walked 1.35 meters

b. In trial 1, it took 7 seconds In trial 2, it took 1.4 secs

c. Trial 1= 1.29/7 = .184 m/s Trial 2 = 1.35/1.4= .964 m/s

d.To figure out the position of trial 2 after walking twice the time, you can double the time and keep the speed as a constant. My assumption is that the walkers position would be 2.69 meters.

8. a. d= (40/3600)(0.5) = .006 miles

b. d= (40/3600)(1.5) = .167 miles

.167- .006= .161 miles further with a reaction time of 1.5 rather than .5 reaction time

c. d= (35/3600)(.5) = .005 miles

d= (35/3600)(1.5) = .0146 miles

.011 miles further with reaction time of 1.5 than of reaction time of .5

d. d= (48/3600)(.5) =.007 miles

d= (48/3600)(1.5) = .02

.013 miles further with reaction time of 1.5 then of reaction time of .5

e. d= (28/3600)(.5) = .004 miles behind to avoid collision ahead.

f. d= (40 miles/ hr)(1sec) = (211200 feet/ 3600 sec)(1 sec) = 58.6 feet

58.6 feet/15 feet = about 3 car lengths

9/27/11 average veloctiy: total distance/ total time velocity= d/t time= d/v distance= tv

a. ) 150 feet = (t) (40 mi/ hr) 150 feet= (t) (211200 feet/ 3600 sec) t= 2.557
 * Sample problem 3**

b.) Witnesses say that the driver was under the influence of alcohol. The average reaction time is about .2 seconds. Alcohol is a factor that effects and offsets reaction time because it slows down function.

9/28/11 1. a. The cars are traveling at a constant speed. b. The cars were traveling at a constant speed, then went faster and then went back the first, constant speed.
 * Physics-To-Go**

2 a.

2b.



3. d=vt d= (350feet/sec)(20sec) d= 7000 feet

4. a. d=vt 215 miles=(v)(4.5) 47.7 miles per hour

b. She was going a constant speed of 47.7 mph the whole trip because if she went faster for a period of time, the time it took her would have been decreased.

5. d=vt 5 miles= (v)(.25) v= 20 miles per hour

6. a. the car is traveling at a fast, constant and then stops b. the car starts off traveling away at a fast constant speed, then stops, and traveled towards at a slower speed c. the car went away at a constant speed, the changed to a different constant speed d. as the car traveled slowly and increased its speed

7. a. d= (25m/s)(.2s) d= 5 meters

b. d=vt = (16m/s)(.2s) =3.2 meters

c. d=vt d= (80.6)(.4) =32.26 feet

8. a. The average reaction time is .25 secs so they should be able to stop in that amount of time. Experts are sure this a safe distance between the car ahead is because they have tested it. b. Yes on a rural road both cars are moving slower so there is less distance in between but on highways there will be more distance between the two.

9. a. about 33 feet with your eyes closed. b. no this is not longer than the length of the classroom because the classroom is about 35 feet long.

10. a. 44 feet

b. about 3 automobiles

c. 22 about 1.5

d. 66 feet 4.4 cars

e. The distances changes by 44 feet

11.

1. a. 80 Mile Trip
 * Active Physics Plus**

b. 100 Mile Trip

2..

3. a.) I would predict that the average speed of the trip is about 20 mph. b.) 150 miles/ 8 hours = about 18.75 mph is the average speed of the trip.

- A safe following distance between your automobiles is about 2 seconds. This is a safe time in which gives you enough room to stop the car if necessary. - To decide a safe following distance, you should take in account the speed and condition of roads.
 * What do you think now?**

__Section 4__


 * What do you see?**
 * the light is green for the yellow and red car
 * boy and dog look like they're sprinting across street and dodging the red car
 * red cars front wheels are not on the ground
 * yellow car is at a stop
 * light just turned green
 * red car was anticipating the green light and took off right away
 * onlooker seems old
 * looks like a city street
 * no crosswalk


 * What do you think?**


 * both cars are going forward
 * accelerating
 * will both reach the same final velocity
 * because the car is lighter, it'll reach 30 mph first
 * it will also take longer for the bus to stop

1. a.) I predict that if the cart is traveling down the ramp, the cart will start at a constant speed and then increase its velocity.
 * Investigate**

b.) graph one: travels faster in the beginning graph two: with time, the speed increases graph three:the cart is traveling at a constant speed graph four: the cart does not move

c.) when the car is released on the ramp, the graph will start off at 0 and then quickly increase its velocity

2. a.)

b.) I was generally correct with my prediction, the curve shows the slope increasing gradually.

c.).

A and B lines are tangent lines.

d.) As time increases, the distance increases.. this shows that the velocity is increasing.

e.) It starts at 0 (no velocity) as it moves down the incline as time increases, velocity increases.

3. a.

b. My prediction was mostly correct, the graph starts at 0 because the cart did not have any velocity at rest.

c. As the time increases, the slope does not change, there is a constant slope. The slope is expressed with the units (m/s^2). The slope is equal to the acceleration.

d.The acceleration stays constant, exactly the same.

e. __slope: change in veloctiy/change in time= velocity final- velocity initial/ time final- time initial__ = .50 m/s - .35 m/s / 1.60 s - 1.35 s = .15 m/s / .25 s = 0.6 m/s^2

4. a. it will start at the highest position on the graph and curve down

b. it will start at the highest position and will go constantly diagonal

5 a. d-t graph

v-t graph

b. My prediction for 4a. was generally correct the graph started at the highest position and curved in and down as time increased. My prediction for 4 b was incorrect. What really happened was that the velocity started off negative because the cart was traveling toward the sensor, then the velocity became positive after the cart turned around.

c. The slope decreases over time in the distance vs time graph. This occurs because the speed of the cart decreases with time.

d. There is a constant slope on the graph. This occurs because the cart is traveling at a constant speed.

e. the slope is 0.4/0.5 = 0.8 m/s

6. a.) d-t graph since the cart is moving away from the motion detector, the graph will start at 0 (at rest) and will curve upward showing that the speed slowly increases. b.) v-t graph



7. a.) d-t graph

v-t graph

b.) My prediction for the distance vs. time graph was correct in stating that it will start at 0 (at rest) and curve upward to the right portraying the increase of speed as the cart travels away from the motion detector. Also I was correct with the prediction of the velocity vs. time graph in stating that the graph will start at the highest position and be a diagonal line to the bottom right.

c.) the slope of the distance vs. time graph is positive and increasing distance as the car travels further away with time.

d.) the slope of the velocity vs. time graph is negative because as the car travels away with a push, it starts off at a high velocity and then that decreases.

8. first graph: the motion detector was placed at the top of the ramp and the cart was released from the top of the ramp and accelerating away from the sensor second graph: the motion detector was placed at the bottom of the ramp and the cart was pushed from the bottom of the ramp up it and away from the sensor. third graph: the cart is being pushed away from the sensor down the ramp (positive slope) fourth graph: the cart is being pushed towards the sensor (negative slope)

9. 11. a.) velocity-time graph

b.) the velocity changes the most during 0-2 seconds.

c.) the velocity is the least around 10-13 seconds.

d.) the acceleration is greatest between 0-2 seconds and least from 2.9-4.2 seconds

12. a. 15/0.9 = 16.6 ft/s

b.

c.) The table indicates that the greatest acceleration was going 44 feet in 2 seconds. On the graph, 0-2 seconds has the greatest slope.

__**Physics Talk**__

A.) Galileo- "father of motion" B.) Vectors - speed--> magnitude only (scalar)........ Velocity--> mag&direction
 * acceleration- the change in velocity with respect to a change in time
 * ^how fast the velocity changes
 * velocity is the speed and direction
 * a vector quantity has magnitude and direction
 * speed vs. velocity...

on the coordinate plane: right/uppositive.. left/downnegaticve point both in same direction.. speed up .. opposite directions.. slow down

C.) Way to change velocity 1.) slow down 2.) speed up 3.) change direction
 * when you change direction--> you accelerate
 * when driving on curves, there is a change in direction which means a change in velocity
 * acceleration- velocity changes as time passes

D.) Negative Acceleration
 * negative acceleration- (cart going up ramp) final v was less than initial v (velocity is decreasing)
 * positive acceleration- velocity in respect to time= positive
 * scalar quantities- has size but not direction


 * units to measure acceleration is velocity over time
 * on graphs- distance is on y-axis and time is on x-axis

E.) 3 ways to show/depict acceleration way #1= strobe photo X X X X X X

way #2= graphs

a.) away from motion sensor- d-t = positive... curve upwards v-t = positive... starts at 0 then goes up change in velocity over change in time= accerelation find slope/ velocity on curve.. use a tangent line.. find the slope in the tangent line- change in distance over change of time is velocity

- d-t= position doesn't change.. at rest (straight line) -d-t= position changes at a constant rate- starts at 0 linear up -d-t= position increaces at a non constant rat- up curve
 * constant acceleration= a curve
 * tangent line- slope on tangent line to curve gives speed
 * comparing motion graphs:

v--t= at rest.. no change v-t= with a constant velocity- constant v-t= constant acceleration= speed increases over time

way #3= equation Aavg= change in velocity over change in time

acceleration times change in time= change in velocity

change in time= change in velocity over acceleration

Kinematic Equations: (describing motion) __Given:__ velocity= change in distance over the change in time

velocity= Xf-Xi over Tf-Ti

velocity average= Vi+Vf divided by 2 ... or 1/2(Vi+Vf)


 * equations of motion**

1. Velocity is a vector- direction. Yes because the velocity tells the direction and 0 acceleration can just be moving at a constant speed. 2. Yes because objects are being pulled down by gravity. When a ball reaches the top of its path it pauses for just a moment before gravity pulls it back down. 3. Two exact cars can have the same acceleration but then one can accelerate longer and then will have a greater velocity. 4. Some cars can accelerate faster than others but still go the same exact speed. 5. Yes for instance when merging onto the highway and getting into the left lane, you must accelerate and as you are accelerating, other cars are passing by. 6. On the road it doesn't matter what direction you are going in, just the speed. The units in the US for speed-limit signs is usually in miles per hour. 7. a= 2mi/h / sec a=2mi/3600s / 5/1 sec a= 2mi/3600 x 1/5 sec a= .003 mi/s^2
 * Physics to go** #1-12, 14

a.) t= 2mins= 120 secs vf=vi+at vf= 0mi/s + (.003)(120) vf= .36 mi/s

b.) change in X= 1/2 (Vi+Vf)t change in X= 1/2 (0+.36)120 change in X= 21.6 mi

8. a.) 75 m/s b.) (75+0)/2= 37.5 m/s c.) d=1/2(75m/s)(9s) d= 337.5 meters d.) this cars acceleration is also 75m/s, the average speed during acceleration was about 37.5m/s, and (d=(75)(8)) it traveled 600 meters.

9. Vi=4.5 m/s Vf= -0.6 t= 1.3 sec

a.) .6 m/s b.) d=rt d=(.6)(1.3) d=.78 m

c.).78=(.6)(1.1) d.) trial c would get her from second to third faster because of the quicker slide.

10. a.) The top speed recorded was about 11 m/s. b.) 9/7.5 a= 1.2 m/s^2 c.) If the object was released from higher, the objects acceleration would stay the same.

11. a.) graph B would show the boys v-t as he coasts up the hill b.) graph D shows the d-t as he coasts up the hill. c.) graph B shows the acceleration as he coasts uphill. d.) graph A shows the boy going down the hill e.) graph F shows v-t of the boy going up hill then down hill f.) graph C shows the boy at the top of the hill going down.

12. a.) e-f b.) a-b c.) d-e d.) f-g e.) over 500 meters f.) the car was back at rest when completed

14. d=vt 100m/s=

**__Section 5__**


 * what do you see?**
 * car stopping short to avoid hitting moose
 * rural road
 * traveling too fast
 * moose was already walking across the street as the car came
 * looks like winter-time


 * what do you think?**
 * you must consider the road/ weather conditions
 * if there is anyone behind you
 * your speed
 * condition of your car

__**Investigate**__ 1. a.) prediction of distance vs. initial velocity

b.) I predict that as the distance increases, so does the velocity as it travels down the ramp, then once it travels on the floor it will no longer accelerate it will slow down and come to a stop.

4.

5. a.)

b.) With a higher initial speed, there is a greater breaking distance.

c.) My predicted graph is similar to the data graph because both show that as initial velocity increase, the breaking distance increases.

6. a.) doubling the initial speed quadruples the breaking distance.

7. a.) tripling the initial speed also effects in a very vast increase of breaking distance, it makes it 9 times as great.

b.) I predict that going quadruple the initial speed would make the breaking distance 16 times the original.

8. a.) the braking information is located on page 116, under fuel economy.

b.)I expect the breaking distance to also be around the ratio of 80/60 because if you increase the initial velocity by 80/60 the car will also have an increase in breaking distance and these two measurements should be relevant and correspond.

c.) This information also relates to my data because as the initial velocity increases, so does breaking distance.

NOTES:

__**What do you think now?**__
 * in order to determine if you will be able to stop in a safe distance between you and the animal, you will need to consider
 * speed of your car
 * how close the animal is

__Equations__ __**What does it mean?**__ as the velocity of the car increases, the breaking distance of the car also increases


 * __How do you know?__**
 * the investigate showed us that when increasing the initial velocity, it increases the breaking distance.

//**Physics-to-go**// 1. this graph shows an exponential growth

2. Automobile A is safer because at a higher velocity, it has less breaking distance than automobile B. With less of a breaking distance, that means the car is able to come to a safe stop quicker.

3. Vi= 30 mph X= 20 m

(30)^2/2a = 20 a= 22.5

a.) 30/2= 15 mph= 4 times X= 20m =5 m b. 60 m c.) 30 m d.) 45 m

4. reaction time = .9 sec moves 30 m to stop x= v times reaction time X= (10)(0.9) X= 9 m total stopping distance= 39 meters

5. At 30 mph I would expect the car to travel about 40 meters before reaching a stop.

6. The breaking distance for 50 mph is about 112 m and about 65 m for 30 mph.

7. No it does not include the reaction time, but everyone's reaction time is different. I think the reaction time should be included on this sheet because if the driver of the vehicle has a slower reaction time, it will take the car a bit longer to come to a stop because of the different factors.

__**Section 6**__
Learning Outcomes:

investigate the stop and go zone distances

investigate factors of overlap and dilemma zones

we will be using excel


 * What do you see?**
 * the light just turned red, it was yellow prior to it
 * the red car is last minute coming to a stop
 * green car traveling through intersection
 * the green car will continue to go through the light
 * green car is accelerating
 * red looks like its ending up in the middle of the intersection


 * What do you think?**
 * if all traffic lights stay yellow for the same amount of time, the driver would then be sure and able to count and predict if they will be able to make the light or not. If there was a set yellow light more cars would anticipate accelerating to make the light.
 * "it was green so i went"- need to look both ways before and never trust a blinker.

__**Investigate**__ 3. a.) Automobile B will be able to make it through the intersection because the given information states that automobile A, which is behind automobile B, will make it through the light. b.) Automobile A is in the go zone and automobile B is in front of A. c.) Yes, if A is in the go zone right now, then clearly another car could easily make it. d.) Automobile C is not in the go zone because the given information says that they are unsure if C will be able to make it. If they decide to continue, they could either run the red light, or worse, cause an accident.

4. a.) E is in the stop zone because it is behind D who in the given information is also in the stop zone. b.) No because it is too close to the intersection and most likely not have enough distance in order to come to a safe stop. c.)
 * Stop zone (cars) || Go zone (cars) ||
 * C, D, E || A, B, F ||

5 a.) b.)
 * ** Variable ** || ** Change ** ||  || ** Predicted effect of change **
 * on GO ZONE ** || ** Actual effect of change **
 * on GO ZONE ** ||
 * ty || yellow-light time || increase ty || more cars will go through the light- go zone longer || go zone length increases, stop zone stays the same length ||
 * ||  || decrease ty || less cars will be able to go through the light- go zone is shorter || go zone length decreases, stop zone stays the same length ||
 * tr || response time || increase tr || would respond quicker and be able to stop with less distance- stop zone is longer || stop zone is longer, go zone stayed the same ||
 * ||  || decrease tr || less time to stop- stop zone is shorter || stop zone is shorter, go zone stayed the same ||
 * v || speed limit || increase v || more of a chance to make the light- traveling at a faster speed || go zone and stop zone are longer ||
 * ||  || decrease v || less of a chance to make the light because traveling at a slower speed || go zone and stop zone are shorter ||
 * a || negative acceleration || increase a || it could cause accidents because of stopping short || decreased length of stop zone, go zone stayed the same ||
 * ||  || decrease a || the car would need a longer light for a longer stopping distance || increases stop zone, go zone is the same ||
 * w || width of intersection || increase w || there would be more cars in the go zone able to go through || go zone smaller, stop zone the same ||
 * ||  || decrease w || less cars in the go zone, would be tight and less would be able to make the light || go zone longer, no effect of stop zone ||

6 a.)53 meters b.) If the yellow-light time is increased to 3.5, the go zone will be increased. c.) Yes, increasing the time of the yellow light would increase the d.) the distance of the go zone changes with the time of the yellow light.

8. a.)The effect caused by the change of variable makes sense because they are the factors that determine the go zone. b.) Most of my predictions were generally accurate. I thought about it by how many cars would make or not make the light. c.) (speed of vehicle)(the time of the yellow light) - (width of the intersection)= go zone d.) The variables are in the formula for the go zone because they effect the length of the go zone. e.) The variables do not appear in the formula because they do not affect the go zone.

9. a.) to find the stop zone= v(tr)+v^2/(2a) b.) The yellow light time and the width of the intersection do not appear in the equation because they do not affect the stop zone. c.) you need to react, decrease the velocity, and use negative acceleration in order to stop.

Part B: 1. Car A= stop Car B= go Car C= go Car D= stop

2. Car E= stop Car F= stop Car G= go Car H= either

3. Car J= stop Car K= go Car L= stop Car M= go

4. a.) There is a longer stopping distance in intersection 1, an overlap in the stop and go zone of Intersection 2, and the go zone is shorter in Intersection 3. b.) In Intersection 2, if the light turned yellow while traveling in the overlapping section, depending on my velocity and the car behind me, I would need to make a decision to either safely stop or continue going. I would most likely make and go through the light, c.) If the light turned yellow while in the gap between the stop zone and go zone, also like (b.) depending on my cars velocity and the car behind me, i would ned to determineif it issafe to stop or continue. d.) Overlap zone= intersection 2 Dilemma zone= intersection 3

__**Physics to go**__ 1. a.) GZ= (15 m/s)(4s) - 15 m GZ= 45 m

b.) SZ= (15 m/s)(1s) + 15^2 m/ (2x5) SZ= 37.5

c.)

2. a.) GZ= (30 m/s)(4s) - 15 m GZ= 105 m

SZ= (30 m/s)(1s) + 30^2 m/ (2x5) SZ=120 m



b.) GZ= 25 meters SZ= 20 meters



3. The increase in reaction time caused by listening to loud music does not affect the go zone because it is not a factor in the formula to find the go zone. However, reaction time affects the stop zone because it is a variable in the formula for the stop zone.

4. Poor brakes does not play a role on the go zone because if the automobile is in the go zone, brakes are not applied. But poor braking systems affect the stop zone because the brakes determine how and when the car will come to a stop and it must be within the stop zone.

5. The reason for the delay after the light turns red and the cross street does not turn right away is to give a second or two for possible cars making left turns or last minute cars crossing the intersection.

6. I feel as though the numbers in the countdown on the light would be a counterproductive method because I think it would distract drivers by having them just pay attention to the numbers and not mainly focused on the road, which then would increase and offset their reaction time which would affect the stop zone.

7. A GZ= 48 m SZ= 52 m negative= unsafe B GZ= 72 m SZ= 52.6 positive= safe C GZ= 48 SZ= 48.6 unsafe

D GZ=48 m SZ=64.6 unsafe

E GZ= 40.5 m SZ=34.07 m safe

8. I feel like painting lines at all intersections to mark the stop and go zones would be a good idea because not every intersection is the same because of the area, time of yellow light, speed, and many other factors. With exact boundaries of safe stop and go zones, i think it would prevent accidents and doubts whether to go or stop with a yellow light.

9. Dear Mom and Dad, I believe you could trust me borrowing your car today to pick up my friend. In physics class, section 6 made me become aware of the stop zone, go zone, overlap and dilemma zones. I understand that my speed, length of the yellow light, and the width of the intersection affects the go zone. The go zone is the boundary in which it is safe to continue traveling through the intersection. I also learned that my speed and reaction time determine the stop zone. The stop zone is the boundary in which it is safer to stop the car in in order to not run a red light. The overlap zone is the zone in which either decision is safe, going or stopping unlike the dilemma zone where it is risky and causes drivers to panic whether to stop or go and possibly run a red or stop short and cause and accident.

__**Essential Question**__ 1. What does it mean? - What factors determine size of GZ, SZ, and whether an intersection has a Dilemma Zone
 * velocity of the car
 * reaction time
 * width of intersection
 * yellow light
 * negative acceleration

__**Section 7**__
What do you see?
 * mountainous thin road
 * red car swerving
 * took the turns way to fast
 * about to fall of the side of the cliff
 * a sign showing the curves ahead

What do you think?
 * The sign is indicating to slow down because traveling at too high of a velocity on a bend on the road is unsafe. Drivers start too lose control of the car at that high of a velocity.
 * Your speed applies to how sharp the curve is.

circular motion equations:

friction equations:

force is a push or a pull centripetal is a force moving toward the center

__**Investigate:**__ 1.) b When the string is no longer directing the car, it is changing direction and following the tangent.

2. a.) the string pulls the car toward the center b.) the car follows the tangent line

3. a.)

4. 14 cm 6. a.)19.98 secs b.) 10rev/19.98s = .50 revs/sec= 30 revs per minute c.) ^ 0.50 revolutions per sec d.) Measuring ten revs is a better technique in order to get a more accurate answer. You can get an average time of how much time it takes to complete a revolution. e.) 2.5 revs

7. a.) (2)(3.14)(15) m/ (.5) s = 188.4 m/s

b.) trial one= 10.32= .96rev/s trial two= 8.7= 1.14rev/s trial three=8.59= 1.16rev/s

8.6 seconds= 1.16 rev/s (2)(3.14)(.15m)/ (1.16) = .81m/s

8. a.) I think the sandpaper will cause the washer to stay on the turntable better and slow down the speed when it leaves. b.) 14.86 secs 10 revs/14.86 s= .67 revs/s c.)(2)(3.14)(.15)/ (.67) = 1. 41 m/s d.) (2)(3.14)(.15) /(1.06) = .89 m/s

9. a.) The smaller the radius, the higher speed the object can withstand. b.) (s) || Time of 1 rev (s) || Time of 1 rev (s) || Average Time of 1 rev (s) || Circumference (cm) || Maximum Safe Speed (m/s) ||
 * Radius (cm) || Time of 1 rev
 * 13 || .55 || .62 || .57 || .58 ||  ||   ||

This investigate made students recognize and understand the importance of the effect of the //centripetal force//. To demonstrate this, students used a toy car attached to a string in order to keep it moving in a circular motion. Once the string was released, the car no longer followed the path and instead //traveled tangent// to the circle. __//Newtons first law//__: "an object in motion will stay in motion at a constant speed and travel in a straight line unless a force acts of it" when an object travels on a curved path- there is a force acting upon it when the string directs the car in a circular motion by applying tension and friction, the force is always //toward the center// friction of the tires on the road cause the car to keep moving in the circle when the friction is removed for example when icy... car travels in a straight line centripetal force keeps the object moving in a circular path... either the tension in the string and the friction between the object and the surface the speed remains constant when the object moves in a circle but the velocity changes because the direction changes= acceleration when a car changes directions it is accelerating= change in velocity with respect to time //centripetal acceleration:// acceleration associated with an automobile changing directions
 * Physics Talk**

force (f)= units are in newtons (N) 1.) friction is= (Ffr) units are (N) static friction vs. kinetic friction static non moving..stays holds it down...kinetic moving 2.) tension: (Ft)...(N) 3.) normal: (FM)....(N) 9.8newtons= 1 kg 4.) centripetal: (Fc)...(N) Fc= mv^2/r

m= 1 kg r= 1.5m v= distance/time t=10 secs d= 2pir 25 revs
 * 1 kg ball travels in a circular path at the end of a 1.5 meter string..it made 25 revolutions in 10 secs..what is the tension in the string?**
 * given:**

distance= 2pir= (6.28)(1.5) =9.42 m total distance traveled: (25)(9.42) =235.5m

v=235.5m/10 sec =23.55 m/s

Ft= (m)(v^2)/r Ft= (1kg)(23.55^2)/(1.5)
 * =369.735 N**

r=6400 ...= 6,400,000 m v=? t= 24 hr....= 86400sec
 * __Physics to go__ .........** 1 rev= 360 degrees= 2 pi rad= 2 pi r
 * 1.**

v= distance/time= circumference/time= (6.28)(6400)/24 =1674.67km/hr = 1674670m/3600s v= 465.19 m/s

r= 150000000000 m t= 365.24 days...8765.76 hrs v= ? v= distance/time= circumference/time v= (6.28)(1.5x10^8)/ 8765.76 = 1.07x10^5 km/hr
 * 2.**

r= 15cm... .15 m (60 revs/s)(2 pi)(.15)/1rev =(.942 m)(60)/ sec= 56.52 m/s
 * 3.**

(2)(3.14)(.15)/(60) = .0157 m/s

a.) if the curve is tighter, you will lose control of the car b.) there is less friction so there could be a skid c.) the car can skid and lose control
 * 4.**

When a ball is traveling in a blockaded circle normal force is applied
 * 5.** When a string is attached to an object.. the force of tension keeps the object toward the center


 * 6.**

- this means that although the driver may turn the wheel, depending on road conditions and wheather conditions, the car will travel in a straight tangent line.
 * 7.** "a driver may turn the wheels but it is the road that turns the automobile."

v= 270 m/s r= 1000 m
 * 8.**


 * 9.** I believe the first explanation is correct because when making a sharp left turn, your body, like mentioned in the second explanation is expecting to keep continuing in a straight path. Therefore, you find yourself sliding up agains thte passenger door due to the centripetal force.


 * 10.** I believe that the normal force and friction are acting upon a race car as it moves along the track.


 * 11.** highway curves can be the most dangerous because traveling at a high velocity can make you lose control of the vehicle depending on the sharpness of the curve.


 * 12.** The car would end up into the lane of oncoming traffic if the curve bends to the right because the car will follow the tangent line and that is the same for left curves.. the car would travel into the oncoming traffic also because it is follow the tangent line


 * 13.** In order to be safe while driving around curves, you must decrease speed significantly depending on the sharpness of the curve. Rain or ice will remove some friction causing the car to have a more likely chance of skidding or losing control.