Chapter+1

toc 1. You wind up the car and see how far it goes in a certain amount of time. 2. This object works by winding up the car, holding out the meter sick, setting up the timer, and letting go of the car. 3. People who can use this object are people who need to measure time and velocity.
 * Intro Lab**
 * Station 1**

Station 2 1. The object is able to tell how much one object can weigh and if it's balance or not. 2. The object is hooked onto the other object and balances it out. It shows that the blue is less balanced than the red rod. 3. People who can use this are people who see how things can balance.

Station 3 1. The heavy weight weighs down the spring so the spring keeps bouncing. 2. The object works by putting the weight at the bottom of the spring so the spring is allowed to bounce up and down.

Station 4 1. The laser glows through the block and with the harmless spray smoke, you can see the laser. 2. When you shine the light, spray the light with the can of spray smoke to see the laser. 3. Lasers are used by BI, police and detectives. Spray smoke is used for parties and to display smoke. The glass could also be used as a paper weight. 4. The object may be used for detecting secret things that use a light beam.

Station 6 1. The objects project a very high pitched noise. 2. The object works by dipping your finger in water and rubbing your fingers around the top of a glass cup filled with water. When you lower the amount of water inside, the higher the pitch is. 3. People who can use this are people who detect pitch sounds and orchestras. 4. The object is used for other things like detecting pitch noises and could be used with dolphins.

=Section 1=

**What do you see?**
-A yellow car on top of an orange flipped over car. -A blue car speeding, stepping on the breaks when the car sees the accident. -The background is a mountain. -The orange car is leaking something or it was just raining.

What do you think?
Factors that affect the time you need to react to an emergency situation are weather, visibility, speed, car condition, if you're tired or not, if there's any distractions (cell phones, music) and distance.
 * What factors affect the time you need to react to an emergency situation while driving?**

**Youtube Homework:**
Two people, a male and a female, were both partaking in a road test. They first did the road test normally, then a second time talking on a cell phone, and a third time while intoxicated. During the normal road test, they both went through the course fairly successful. The second time while talking on the cell phone, it was proved to be very difficult and challenging. While on the phone, they were given tasks to do, like name 5 things that are in the car. Both of them ended up failing that road test. For the third, they were given alcohol to consume on an empty stomach. The each consumed a little less than .08, below the legal limit, so they could drive with the "drunk" feeling. They both also ended up failing this test, but overall, they failed the cell phone test much more than the drunk driving test.

**Physics Talk**
This lab is about reaction time, and how everyone's reactions and if distractions made things any different. Distractions definitely made reaction times delayed a little. Many drivers can take their eyes of the road for various reasons, and this makes the reaction time becomes even longer. Drugs and alcohol are also another factor that can increase reaction times and are illegal. Personal traits and more things can be a factor in reaction time as well.

__Checking up:__
Distractions affect reaction time because if someone is talking on their cell phone or under the influence, they aren't completely focused on the road ahead of them. Distractions make your reaction time slower so you aren't as aware. Driving under the influence of drugs and alcohol is illegal because it impairs your reaction time. Your reaction time slows down, and it effects your driving negatively. Three factors in addition to distractions and drugs or alcohol are age, fatigue, and gender.
 * How do distractions affect reaction time?**
 * Why is driving under the influence of drugs and alcohol illegal?**
 * Name three factors in addition to distractions and drugs or alcohol that can affect reaction time.**

**Investigate Lab**
Stopwatch: Tori - 11 seconds, 12 seconds, 11 seconds Jules - 13 seconds, 12 seconds, 14 seconds Christina - 14 seconds, 14 seconds, 11 seconds

Ruler: Tori - 7 cm(.12), 11 cm (.16), 7 cm (.12) Jules - 14 cm (.17), 9 cm (.13), 9 cm (.13) Christina - 13 cm (.17), 10 cm (.14), 12 cm (.15)

Ruler with green and red: Tori - 11 cm, Green, 19 cm, Green, 32 cm Jules - 24 cm, Green, 17 cm, 22 cm, Green Christina - 22 cm, Green, 31 cm, 19 cm, Green

Distraction: Tori - 57 cm, Green, 45 cm Jules - Green, 37 cm, 25 cm Christina - 25 cm, Green, 72 cm

Clap: Tori with clap - .23, .20, .20 without clap - .35, .32, .29

1a. They weren't the exact same, but they were both pretty similar. They weren't the same because everyone has a different reaction time to certain things. 1b. The most accurate was probably the stop watch because as soon as you see someone stop, you immediately stop as well to see your reaction.

2a. Method B: .12 is the fastest, .14 is the average, and .17 is the slowest. 2b. Yes, but they won't be too different as people who are the same age will have a similar reaction.

Distractions: 1. talking on the phone 2. texting on the phone 3. changing the radio 4. eating 5. putting on makeup 6. being tired 7. sneezing/coughing 8. fixing hair 9. looking at the time 10. working with the GPS

**Physics Plus**
Comparing both of the charts, they are exactly the same. They are both very accurate and precise.
 * Time (s) || Distance (cm) ||
 * 0 || 0 ||
 * 0.02 || 0.196 ||
 * 0.04 || 0.784 ||
 * 0.06 || 1.764 ||

Jules: thumb & index finger right hand: 5 cm thumb & index finger left hand: 8 cm thumb & middle finger right hand: 8 cm

**Physics to Go #1-7**
1. Dad - 14 cm Mom - 19 cm 2. When I compared the reaction times, my parents reaction time was a little slower than my classmates. The reaction time of my classmates were pretty similar and low, and my parents were a little different. My dad had a better reaction time than my mother, and my mom's reaction time was pretty bad. 4. A race car driver needs a fast reaction time, but a driver in a school zone should have a faster reaction time. When driving in a school zone, you have to be aware of all the children, teachers, adults, and more. When you're a race car driver, you also need a fast reaction time so you don't crash into any other cars or the boundaries and crash. They don't want the car to flip over or crash. 5. Alcohol, changing the radio, and talking on a cell phone lowers your reaction time. The distractions make your reactions slower, which is never a good thing. 6. The consequences of one's reaction time is someone has a slow reaction time can be a lot. With a slow reaction time, you're more likely in danger and prone to accidents. The slow reaction time can cause accidents easier, because if you don't have a fast reaction time you won't swerve your car or try to get out of the way quick enough. 7. Teenagers often have more expensive insurance for a few reasons. Teenagers aren't as experienced drivers as adults are, and they haven't been driving on the road as long. Teenagers don't have the same focus as adults do sometimes as well.

1 cm - .045 2 cm - .063 3 cm - .078 4 cm - .090 5 cm - .101 6 cm - .110 7 cm - .119 8 cm - .127 9 cm - .135 10 cm - .142 11 cm - .149 12 cm - .156 13 cm .162 14 cm - .169 15 cm - .174 16 cm - .180 17 cm - .186 18 cm - .191 19 cm - .196

**Essential Questions**
Reaction time is the amount of time it takes for someone to respond and react.
 * What is reaction time?**

We measured reaction time in this section by using stopwatches, rulers, and the foot pedal thing. The reaction times from my other classmates ranged from 11 seconds to 14 seconds for the stopwatch, 7cm to 14cm for the rulers, and .20 to .35 for the foot pedal clap one.
 * How did you measure reaction time in this section? What was the range of reaction times obtained by other students in your class?**

Reaction time is a measure of change over time because everyone has a different reaction times.
 * Describe how reaction time is a measure of change over time?**

Reaction time has a lot to do with driving safely. If you have a good and fast reaction time, it will be easily to avoid accidents and swerve your car. With a slow reaction time, you may not be able to avoid as many accidents or something in the road.
 * What relevance does reaction time have to driving safely?**

=Section 2=

**Learning Objectives:**
Calibrate the Length of a Stride Measure a distance by pacing it off and by using a meter stick Identify sources of error in measurement Evaluate estimates of measurements as reasonable or unreasonable

**What do you see?**
I see a little girl and a grown man measuring their steps. The man's steps are a lot bigger than the little girls. There's two pencils for different stops.

**What do you think?**
Yes, I think one of them has made a mistake. I think they have because there is a large difference between 3 and 10. If students reported a difference of 3.0 and 3.1, then they most likely didn't make a mistake. They both measured the same object but one was just a little more accurate than the other.

Precision - how repeatable the measurements are Accuracy - how close the measurement is to the true value

**Investigation**
Tori - # of strides: 34 x 59 = 2006 2261 m - tape measure 2253 m - stick
 * Group || Stride || MeterSticks || TapeMeasure ||
 * 1 || 2006cm || 2253cm || 2261cm ||
 * 2 || 1100cm || 1369cm || 1370cm ||
 * 3 || 900cm || 1369cm || 1370cm ||
 * 4 || 867cm || 1369cm || 1370cm ||
 * 5 || 1598cm || 2253cm || 2261cm ||
 * 6 || 759cm || 1370cm || 1372cm ||

5a. No. The results vary from 867cm to 2,006cm, which is a lot. Also, there are different lengths. 5b. Everyone takes different steps depending on their height and how big or small of steps that they take. 5c. Everyone takes the same length steps. If we do this method, then we'll have closer measurements and it won't be as scattered.

7a. All the measurements do not agree. They vary from 1,369cm to 2253cm. 7b. They do not agree because two of the measurements are different lengths. 7c. Everyone has to measure it from the same spot and not have two different lengths. 7d. If they were given a very long tape measurer, each group probably wouldn't get the same value. Because the tape measurer is very long, it's harder to keep it still and get exact measurements. 7e. No they can't all be exact because everyone measures things differently. There will always be some differences.

8a. No we didn't have any systematic problems. 8b. We didn't have any errors.

**Physics Talk:**
No matter what students used to measure distance, there will always be differences. Measurement differences can vary from .05 to .1 depending on rulers you use, and there may always be random errors. Meter sticks with millimeters have a less chance of uncertainty, although there can still be mistakes if one isn't paying too much attention. There are also systematic errors, which is like saying centimeters are meters. Also, precise and accurate are different things. Precision is when something is all around the same answer and accuracy is when its correct or close to.

Checking Up:
1. The difference between random errors and systematic errors are that random errors are random, and it just may be a different like 8.7, and 8.8. Systematic errors are if the rulers are different sizes or if you have a yard stick and a meter stick, instead of just one.

2. There will always be uncertainty in measurement because no one can will have the exact same measurements, and there will always be differences.

3. The positions of the arrows would have to be very scattered, and not near the bullseye at all.

Do Now 9/22
1. 6.789, 6.784, 6.781 - random 2. Using inches to measure a length instead of centimeters - systematic

S2 Notes - Uncertainty
26.7cm + or - 0.1cm 5,000cm + or - 1,000cm

510 cm + or - 10cm 10.250 cm + or - .001 cm 7.34 cm + or - .01cm

Physics Plus 1-4
1. 10 cm + or - 49.90-50.10 1 cm + or -, 49.99 - 50.01 1 mm + or -, 49.999 - 50.001

2. 2cm

200 cm/s = 1/100 = .01 s time is equal to distance divided by speed With a difference of two centimeters, someone with a pool length of 49.9 could swim it in about 24.9 seconds, while someone with a pool length of 50.1 could maybe swim it in 25.1

3. .006 minutes, .36 seconds 1500 m .60m 15m x =.006seconds

4. The new record may be slower than the previous record because sometimes, with random error, the pools can be different lengths and they all might not be exactly 50m.

What do you think now?
If one student reports 3 m and the other student reports 10 m, yes it is a mistake and a systematic error. If one student reports 3 m and the other student reports 3.1 m, no it was not a mistake it was just a random error. You can try to reduce random errors but being more careful and don't make any silly mistakes with rounding, and go to the exact measurement.

Essential Questions
If my friend mistakes a yard stick for a meter stick, this would be a systematic error. Random error does affect accuracy.
 * Is this error random or systematic? Which of these types of errors affect precision or accuracy?**

I know that the jeweler can't be sure because not everything is always exactly exact and there are always some uncertainties
 * How do you know that the jeweler cannot be sure that it is exactly 1 oz?**

You can trust experiments because as long as you measure correctly with the right measuring tool and you're careful, you will get a pretty accurate answer hopefully.
 * How can you trust experiments if all measurements have uncertainties?**

The consequences of not estimating your stopping distances are that you will crash your car, and cause an accident which is why you should always drive carefully, be paying attention and measure accurately.
 * What are the consequences of not estimating stopping distances accurately or the width of a space between your vehicle and other vehicles while driving?**

Physics to Go
5. All the measurements on the food labels are either very accurate, or very close to accurate. Food labels cannot lie that is illegal. 6a. No it's not reasonable because it's about 5 ounces of soda per cup which is not enough 6b. Yes it's reasonable because the average tank is around 300 miles and it takes about 200 to get from Boston to NYC.

7. No it's not because the width of a room isn't that big, meanwhile the width from my school to my house is a lot farther and bigger.

8a. To guarantee you won't be going over the speed limit you should go 60 mph.

=Section 3=

Learning Objectives
Define and contrast average speed and instantaneous speed. Use strobe photos, graphs, and an equation to describe speed. Use a motion detector to measure speed. Construct graphs of your motion. Interpret distance time graphs. Calculate speed, distance, and time using the equation for average speed.

What do you think?
The blue car stopped short and then the red car bumped into it, and the yellow car was speeding so they stopped once they saw the other cars stopped but they crashed into the cars. The other cars across the street have the right amount of distance.

A safe following distance between you and the car in front of you should be big enough that you know you will have enough time to react.

You decide what a safe following distance is by letting yourself have enough time to react and then giving yourself a little more space in case of any emergencies. Speed and weather are also factors.

Investigation
2a. 2b. 30mph cars were closer together than the 45mph cars, and they were much more spread out. 2c. You decide how far apart to place the 60mph cars because you compare it to the 45mph cars and make the space between bigger.

3a. C is traveling the slowest, meanwhile A is traveling the fastest. I made my choice because of the distance between the cars. 3b. Each automobile is traveling at a constant speed. Yes because the distance between the car is the same.

4e. The first graph was walking away from the motion sensor and over 3 seconds, it went from about 2.2 to .1. The second one while walking towards the motion sensor was also 3 seconds, and started at .1 and ended up at 2.2. The third graph was walking away from it at a normal speed then walking back very slowly which was like 11.4 seconds, and started at .1 then went to 3 then ended at .8. The fourth graph walking in both directions really fast was about 4.2 seconds, and started at .1 then went to 2.2, and back down to .6.

6b. You can determine because the the first line would be the slower walking away because it's a longer line and the dots are closer together. The second line would be the faster walking because it's a shorter line and the dots are farther apart.

7a. Distance is 2.2 7b. It took 4.9 seconds 7c. .4489 7d. If it went for 9.8 seconds, it would be 4.4m. Our assumption is the speed will stay the same.

Physics Talk
Model 1: Strobe Photos - used to illustrate the velocity of an object by the distance between the object in each picture

Model 2: Solving equations - v = d/t distance/time

pg. 41-43, 46

Model 3: Describing Motion and Speed, Distance vs. Time Graphs Graphs are a good way to describe visual data slope is always the speed in a distance time graph A) not moving

A kilometer is a little less than 2/3 of a mile. The steeper the slope the faster it's going to be.

Checking Up Qu3$+!0n$
1. The average speed of a vehicle is different from instantaneous speed is that instantaneous speed is a speed at a given moment while average speed is the total distance traveled divided by the time it took to travel that distance. 2. Speed and velocity of an object are different because velocity is the speed in a given direction and speed is the distance traveled per unit time; speed is a scalar quantity, it has no direction 3. If the distance time graph shows a straight inclined line, it means that the line on the graph is going faster at a constant speed. 4. Reaction time affects reaction distance because the distance that your automobile travels until you respond is known as your reaction distance.

Physics Plus


1. 2.

3a. I estimate it will be around 20. 3b. 150/8 = 18.75 total distance divided by total time 4. 60 velocity = 40 distance = 40
 * Speed || Distance || Time ||
 * 50 || 50 || 1 ||
 * 25 || 50 || 2 ||
 * 10 || 50 || 5 ||
 * Speed || Miles || Hour ||
 * 20 || 20 || 1 ||
 * || 20 ||  ||
 * 40 ||  ||   ||

Wh@t do you think now?
1. A safe following distance between your automobile and the vehicle in front of you is where you have a good amount of time to react if they stop short or anything like that. You need to be outside of your reaction distance time. 2. You decide what a safe following distance is by seeing if you have a fast or slow reaction time and then giving yourself the right amount of distance. Distractions can impact your reaction time which impacts your reaction distance.

Essential Questions
It means to say that the speed of a vehicle in an hour is 40.
 * 1. What does it mean to say that the speed of a vehicle is 40mph?**


 * 2. How would you go about measuring the speed of a vehicle? What measurements would you have to take? What calculations would you have to perform?**

You would go about measuring the speed of a vehicle by seeing how far you went and you would have to know the velocity, time and distance.

Three models can represent a car moving at 20mph because
 * 3. How can all three models represent a car moving at 20mph.**

4. Reaction distance depends on your reaction time and speed because if you have a fast reaction time, you'll have a small reaction distance and if you're going really fast your reaction distance will be longer because you're going to cover more ground.

Physics To Go
1a. In this strobe photo, the car is going at a constant speed the whole entire time. 1b. In this strobe photo, the car is going at a constant speed for a little, then changes speed. 2. 3. (t)(v) = d 20 x 350 = 7,000 feet 4a. 215 miles / 4.5 hours = 47.8mph 4b. No, you do not know how fast she is going. You don't because you only have the average speed. 5. v = d/t 1/4 =.25 5/.25 = 20 6a. They are traveling away from the sensor at a constants speed but then stops as the time continues to go on. 6b. They are traveling away from the sensor, then come to a stop. Then continue to keep going, although in the opposite direction as before but in a slower speed than before. 6c. They are traveling at a constant speed then the speed does increase up to a constant speed. 6d. They are walking away from the sensor and increase speed over time. 7a. 25=d/.65 25x.65=16.25 is the distance 7b. 16= d/.65 d= 10.4 this distance is less than a because we are going slower 7c. 25= d/1.3 d=32.5 is how far you would travel

8a. They can't be completely sure that this is a safe following distance but this is a good and close guess. 8b. no it would not be equally as safe because when you are going faster you should have a farther and longer following distance.

9a. 100=d/.33 100x.33=33 feet 9b. No this is not longer than our classroom 10a. d=vt 88 x 0.5 = 44 ft. 10b. 44/15 = 2.93distances (about 3 car spaces) 10c. 88x2 v=44 (44)(.5)=22ft. 1 to 1 and a half car spaces 10d. 10e.

11

11. v = 60mi/h =88 ft/s

v=d/t

22ft in .25 seconds 44ft in .50 seconds 66ft in .75 seconds 88ft in 1 second

=Section 4=

Learning Objectives
Measure a change in velocity (acceleration) of a cart on a ramp using a motion detector. Construct graphs of the motion of a cart on a ramp. Definite acceleration using words and an equation. Calculate speed, distance, and time using the equation for acceleration. Interpret distance-time and velocity-time graphs for different types of motion.

What do you see?
The guy in the red car is clearly going very very fast and accelerated quickly. His hat and scarf are flying backwards and there is smoke coming from the car. The light is green so they just went really fast when it turned green. The dog and the boy are running across the street trying to make the light.

What do you think?
A similarity is that they are going to start up at the same time. The differences in both vehicles are that the bus will take a much longer time to get up to 30 mph while the regular automobile will only take around 6 or 7 seconds. Distance wise, the car is going to cover a lot more ground.

Physics Talk
Using no technology whatsoever, Galileo applied mathematics to make measurements of acceleration. Without technology, he had a ball roll down a slight incline to test. Acceleration is change in velocity with respect to time. With the ball rolling down at a constant speed, its a straight line on a velocity vs. time graph. A car accelerate much faster than a bus would be able to. Speed and velocity are different, and velocity has a change in direction. If the final velocity is less than the original velocity, it's a negative acceleration. Vector quantities has a magnitude and a direction. Scalar quantities has magnitude but no direction. Speed is scalar, (34 mi/h - tells you no direction) Velocity is vector (34 mi/h south)



1. A car is traveling at a velocity of 40 m/s, it slows down to a stop in 3.5 seconds. What is the car's acceleration? 2. A bicycle accelerates from 0 m/s to 15 m/s in 7 seconds. What is a?



Homework
HI okay i did the homework the day i was supposed to but i'm lazy like you know and i never took pictures of it until now....don't mark me late that would be greatly appreciated because you know i did it hey my hand covered that.....but it's supposed to be 19.3 m/s



Everything due Monday



1. Velocity is the slope of distance vs. time graph because slope equals rise/run. Rise is the distance, meanwhile run is the time. Since rise/run = distance/time, they're the same thing. So, distance/time equals velocity which is why it's slope. 2. Acceleration is the slope of a velocity vs. time graph because once again, slope is rise/run. Rise is equal to velocity and run is equal to time. Velocity/time equals acceleration therefore acceleration is the slope. 3. You need to use tangent lines to find instantaneous speed because in order to get a slope you need two points.

=Section 5=

Learning Objectives
Plan and carry out an experiment to relate braking distance to initial speed Determine braking distance Examine accelerated motion

What do you see?
The car was clearly going pretty fast and had to come to a halt and braking because they saw a moose. The back tires are lifted up and you see the wind from the car. He has a shocked expression on his face so he wasn't expecting it. Also you see smoke from the rubber on the tires.

What do you think?
If something goes right in front of your car, old breaks will impact how quickly you can slow down. The speed you're going, reaction time and reaction distance also have an impact. The direction of your car.

Investigate
(first run 320cm) second run - 300 cm (1.75) third run - 350 cm (2) fourth run - 280 cm fifth run - 260 cm sixth run - 150 cm (.75) seventh run - 250 cm (2)





1. 6. Run 2 has a braking distance of 300 cm and initial speed of 1.75m, meanwhile Run 6 has a braking distance of 150 and an initial speed of .75m. 6a.The effect of doubling the initial speed on the distance traveled during braking would increase the distance very much because if the car is going faster, it will take a while longer for the car to slow down therefore it would go further.

7. The closest one to three times is Run 3 that has a braking distance of 250 and an initial speed of 2, meanwhile Run 6 has a braking distance of 150 and an initial speed of .75. 7a. The effect of tripling the initial speed makes the distance travel a lot farther too and almost triple the distance, even though ours didn't really show that. 7b. Going four times faster would make the distance very far, probably around four times the distance.

Checking Up # 1, 2, & 3
1. It has undergone negative acceleration because it came to a sudden stop, so it's negative. 2. Like in the investigation, if you have a faster velocity it will take a longer time for the car to get to a complete stop making the braking distance increase. 3. Negative acceleration is used instead of deceleration because they aren't talking about the speed. Negative and positive acceleration are talking about the direction because acceleration is a vector which has direction!!!!!!

Physics to Go # 1-5


=Section 6=

Learning Objectives
Investigate the factors that affect the STOP and GO zones at the intersection with traffic lights. Investigate the factors that result in an Overlap zone or a dilemma zone at intersections with traffic lights. Use a computer stimulation to mathematically model that situations that can occur at an intersection with traffic lights.

What do you see?
The red car stops really short, and the dog is flying out. The back end of the car is up and a police man in the background. The light suddenly turned red. The woman in the green car speeds up to try to beat the light.

What do you think?
1. This would affect the driver's decisions at intersections because some people may try to count the time of the yellow light and try to pass through or wait. Different speed limits will also cause different distances. 2. An intersection with a traffic light can be dangerous because some people try to make the red and speed up, while others will slow down and wait at the yellow light. Also when the stop light goes out because of the power, no one judges when they should stop or go correctly. Also people that just run red lights.

Investigation
3a. Yes, if A can than B can. 3b. Yes because it's the first car and the first car can make it so it's in the go zone. 3c. Yes 3d. No, if automobile c continues it might get into an accident because it may run the red light.

4a. Yes because it's the last car and the car in front of it is in the stop zone. 4b. F is in the go zone, and if it stops then it may cause an accident and d and e might crash into the back of F's car. 4c.

5a. ty, tr, v, a, w 5b.

6a. 53 meters. b. 63 meters. c.Yes since the Go Zone will be bigger

7abc. yellow light time - increases the go zone high response time - increases stop zone speed of vehicle - increases both negative acceleration rate - decreases stop zone width of intersection - decreases go zone

9a. Stop Zone = (B5 * B4) + (B5^2)(2/B6) Go Zone = vty - w S2 = vtr (reaction distance) + v^2/2a (breaking distance) 9b. They don't affect stop zone. 9c.Width doesn't matter because once you're in the intersection you need to go anyways.

1. A - no B - yes C - yes D - no
 * PART B:**

2. E - no F - no G - yes H - yes

3. J - no K - yes L - no M - yes

4a. They are different because the first one is a regular Stop and Go zone, the second one is a overlap zone, and the last one is a dilemma zone. 4b. Your choices would be that you can either stop and go, but both of them are safe.. I would go because if it's in the overlap zone, I think going would be the better decision. 4c. Your choices would be that you can either stop and go, but neither of them are safe. Both choices are risky no matter what because if you stop you might land in the middle of the intersection but if you are going then you might get into an accident or run a red light. 4d. The second intersection has an overlap zone but the third intersection has the dilemma zone.



5a. The relationship between the GO and STOP zone at an unsafe intersection is that if you are at the STOP zone and act like you're in the GO zone and try to make the light, you will run a red light and get into an accident. 5b. It's the overlap zone at 20 m/s. 5c. It's the dilemma zone if the speed is increased 30 m/s. 5d. The intersection is safer now because the slower your speed, the better chance that you'll either be exactly in the go or stop zone and will know what to do, and not the dilemma zone. 6a. The longer it is it will be an overlap, the shorter will be a dilemma.

Physics Talk
Mathematical formula - usually formulas or equations that are used to help us understand something in the real world BUT they don't need to actually relate to real objects Yellow Light Model - used different variables to determine whether to stop or go through a yellow light First part - determine the stop zone and the go zone Second part - determine safety (dilemma or overlap zone)

- includes all positions where you can safely go through a yellow light at an intersection - three variables impact this speed of the vehicle (v): If your speed increases, the Go Zone increases because you can cover more ground in less time. yellow-light time (ty): If the yellow-light time increases, the Go Zone increases because it gives you more time to go through the light. width (w): If the width increases, the Go Zone, the Go Zone decreases because you need to cover a larger distance in the intersection.
 * GO ZONE**

- equation to find the GZ GZ = (v)(ty) - w

-includes all the positions where you can safely stop at a yellow light at an intersection -three variables impact this: speed of the vehicle (v): If your speed increases, the Stop Zone increases because it will take you longer to stop your car. reaction time (tr): If your reaction time decreases, the Stop Zone decreases because you can hit the breaks quicker so there's less of a Stop Zone. negative acceleration (a): If your acceleration increases, the Stop Zone decreases because you slowed down faster so you don't need that big of a Stop Zone.
 * STOP ZONE**

- equation to find the SZ SZ (total stopping distance) = (v)(tr) (reaction distance) + v^2/2a (breaking distance)

Dilemma vs. Overlap Zone Zones that help determine the safety of the intersection

- the intersection is not safe - creates an area where stopping and driving is not safe - you may or may not get t-boned
 * DILEMMA ZONE**

- the intersection is safe - creates an area where stopping and driving are both safe
 * OVERLAP ZONE**

- There is an extra variable, the length of the vehicle - Models that describe how forces affect motion, how light behaves, and how something called energy can neither be created nor destroyed
 * Limitations of the Yellow-Light Model**

Checking Up Questions #1-5
1. The spreadsheet is referred to as a model because it doesn't exactly relate to real objects but it helps us understand. 2. The GO Zone means that if you are in this zone, you can safely go through the yellow light at an intersection. 3. The STOP Zone means that if you are in this zone, you cannot safely go through the yellow light at an intersection and you should stop. 4. The Overlap Zone is when the stop and go zone overlap, and it is safe to either stop or drive. 5. The Dilemma Zone is where the intersection is not safe, and stopping and driving isn't safe.

Physics Plus
1. If you increase your speed, then your go zone is bigger because you cover more ground in less time. If you decrease your speed, then your go zone is smaller because you have less time. 2. 3. 4. 5. At middle speed your overlap zones are formed. Also at low and high speeds dilemma zones are formed. 6.You're not going fast enough to get through the light so it creates an unsafe situation and dilemma zone. 7. It may help the teenager get through the yellow light, although it can be dangerous. If he doesn't make it on time, he risks going through a red light. He also risks getting involved in an accident.

What do you think now?
If all yellow lights were the same amount of time, people would count the seconds of how long it stays yellow for, and would most likely try to make the yellow light. If they do this, this could cause accidents and possibly running a red light if they don't count correctly. An intersection with a traffic light could be dangerous because of yellow lights. When the light turns yellow, a majority of people want to try to make it so they'll speed up. When they speed up, they're affecting the go and stop zone and may run a red light or get into an accident. If a dilemma zone is caused, then this causes danger because it's neither safe to go or stop. If you're going to fast, it'll be hard to slow down in time and you may end up in the middle of the intersection.

Essential Questions
1. Factors that determine the Go Zone are width, speed of vehicle, and yellow-light time. Factors that determine the Stop Zone are speed of vehicle, reaction time, and negative acceleration. 2. 3. GO and STOP Zone Models help you improve your understanding of traffic because formulas and equations help us to understand things but they don't need to actually relate to real life. 4. It can make you a better, more informed driver because when you are coming up to a yellow light, you will be sure not to speed or being going to slow and be going at the speed limit. The speed limit is designed for the intersection so if you're going the right speed, you should be fine.

Physics to Go
1a. Go Zone = 45 1b. Stop Zone = 37.5 2a. Go Zone = 105 (3*4-15) Stop Zone = 120 Dilemma Zone The danger is it creates an unsafe intersection. 2b. 65 60 Overlap Zone 3. It doesn't affect the go zone because reaction time isn't a factor that affects it. It does affect the stop zone and increase in stop zone. 4. With worn tires and bad brakes you won't be able to slow down fast enough causing you to have a greater stop zone which causes a dilemma zone. Going slower will decrease your go zone. 5. Because sometimes people will try to make the red light, so if the other side gets the green immediately then they might get into an accident. Also gives additional time to clear 6. It's not a good idea because with the countdown, the people will definitely try to beat the countdown and the red light. By this, people will start speeding up which increases the go zone. 7A. 48m: GO zone 52.6m: STOP zone NOT SAFE, dilemma 7B. 72m: GO zone 52.6m: STOP zone SAFE, overlap 7C. 48m: GO zone 48.6m: STOP zone NOT SAFE 7D. 48m: GO zone 64.6m: STOP zone UNSAFE 7E. 40.5m: GO zone 34.1m: STOP zone SAFE 8. No because I think it's kind of similar to the countdown idea. I think if people were in the GO zone, they would increase their speed and may even go over the speed limit which defeats the purpose of a stop and go zone. There are too many variables for each person and everyone has a different reaction time, car, brakes, etc.

need to know for quiz: which variables impact which things yellow light time won't do anything to do the stop zone, increase the go zone use equations to solve for anything how go, stop, dilemma, and overlap zone could be formed if you change one thing whats gonna change the other thing and how it'll impact other things

=Section 7=

Learning Objectives
Recognize the need for a centripetal force when rounding a curve. Predict the effect of an inadequate centripetal force. Relate speed to the centripetal force.

What do you see?
The red car was speeding through the windy road. He's clearly going in both of the lanes, so there will be an accident. Only on two wheels, making a really sharp turn, the bigger the car the more likely. Because of the speed the car is about to fall off the road.

What do you think?
1. There's a sign indicating to slow down because on a turn like this where the road is really windy and near a cliff, you should slow down because if you're going too fast you're more likely to be in danger or cause an accident. 2. The amount of how much you slow down is determined by the road itself. If the road is just a slight turn, then you won't need to slow down as much but if it's a sharp turn like the picture above, it's better to slow down.

Investigate
1a. From where the car stops, it will keep going straight. 2a. The string pulls the car in a circle. 2b. We stopped it in front of us so it continued to go forward and straight. 3. 4a. 20 cm 6a. 22. 55 6b. 6c. 6d. 10 spins is a lot more accurate because if you do it more, it's an average. If you do it only once, it will most likely be off. 7.

ON SANDPAPER: 4a. 20 cm 6a. 12. 95



8a. The sandpaper will affect it because you'll be allowed to go faster without it falling off the turntable. 9a. If you have a bigger radius, the turn will be a bigger turn so it's easier to make the turn and you won't have to slow down as much. It's a gradual turn. 9d. The maximum speed decreases as the radius decreases. BIG WASHER: SMALLER WASHER: 10a. With a heavier truck, it affects how fast it can move through a turn because all the bricks make it heavier.The lighter truck would have an easier turn and the bigger car would feel the turn more. 10c. Yes because it slows it down.
 * Radius(cm) || Timeof1Rev(s) || Timeof1Rev(s) || Timeof1Rev(s) || AverageTimeof1Rev(s) || Circumference(cm) || MaximumSafeSpeed(m/s) ||
 * 20 || 3.55 || 3.52 || 3.16 || 3.41 || 125.66 || 3.55 ||
 * 10 || 3.05 || 1.71 || 1.69 || 2.15 || 125.66 || 3.05 ||
 * 3 || 1.85 || 1.19 || 1.05 || 1.36 || 125.66 || 1.85 ||
 * Radius(cm) || Timeof1Rev(s) || Timeof1Rev(s) || Timeof1Rev(s) || AverageTimeofRev(s) || Circumference(cm) || MaximumSafeSpeed(m/s) ||
 * 20 || 1.27 || 1.98 || 2.03 || 1.76 || 125.66 || 2.03 ||
 * 10 || 2.13 || 1.59 || 1.72 || 1.81 || 125.66 || 2.13 ||
 * 3 || 1.18 || 1.38 || 1.10 || 1.22 || 125.66 || 1.38 ||

Physics Talk
Force is required to keep string moving in a car. Newton's law explains the motions. Force - a push or a pull that changes the state of motion of an object

1st Law - an object in motion will stay in motion at a constants speed and travel in a straight line unless a force acts on it. Inertia - The ability of an object of resist a change in its state of motion -an object in motion or rest will stay in motion or rest unless acted on by an outside force.

Centripetal Force - A force directed toward the center to keep an object in a circular path. Centripetal Acceleration - A change in the direction of velocity with a respect of time. - has to be in a circular path

Checking Up
1. Straight is the direction of the force that keeps an object moving in the circle. 2. The name of the force that keeps an object in circle is centripetal force. 3. The force that keeps an automobile is centripetal force. 4. If there is a change in direction the velocity can change. 5. If you speed up, change direction, or slow down. 6. The force that keeps the Earth moving in a circle around the sun is gravity.

Physics Plus


A. f = 1000 (14^2) divided by 40 196 * 1000 = 196000 196,000 divided by 40 4,900

B. f = 1000 (20^2) divided by 40 400 * 1000 = 400000 400,000 divided by 40 10,000

Physics to Go
4a. The radius will go down. 4b. With a slippery road, there is a lot less friction. 4c. There is almost no friction so you should slow down.