Chapter+1


 * __ *Graphics by Justin Schwarz __**

toc

**__What do you see?__**
- Two cars in a crash - One of the cars is flipped over - One of the cars is on top of another car - There is another car trying to avoid the crash - One of the cars is leaking gas - Glass underneath the yellow car

__**What do you think...what factors play a role?**__
-The driver must be paying attention -Must have good senory abilities -Able to actually drive -Knowledge

- Investigate 1

+Foot from gas pedal 1A). I would estimate that it would take around a half second for my foot to react -Investigate 2
 * || Time in seconds ||
 * Trail 1 || .372 ||
 * Trial 2 || .387 ||
 * Trial 3 || .337 ||

+Foot after partner claps

1A). I would estimate that it would take about .25 seconds to react -Investigate 3
 * || Time in seconds ||
 * Trial 1 || .35 ||
 * Trial 2 || .39 ||
 * Trial3 || .30 ||

+Comparing stop watches with partner

1A). I would estimate the time for me to react after my partner stops would be about a half second -Investigate 4
 * || Time in Seconds ||
 * T1 || .32 ||
 * T2 || .21 ||
 * T3 || .20 ||

+Catching the ruler while partner tries to confuse other partner 1B). The average amount traveled before I reacted was 13cm 1C). The average reaction time would be around .15 seconds
 * || Length in cm ||
 * T1 || 15cm ||
 * T2 || 3cm ||
 * T3 || 8cm ||

__**Reviewing the Methods of Measuring Time:**__
__**1A:**__ The reaction times in our tests vary due to the ability of a person being able to process information and send it to the part of the brain that controls their reactions. Some people have more acute reaction times than others due to unknown reasons. __**1B:**__ in out tests, I found that the meter stick was most likely the most accurate way to judge a persons reaction time. For example, it showed the exact amount of distance traveled when the person reacted which is important since the ruler can give a finite point whereas the stopwatch may have been stopped too early or too late by the observer.

__**2A:**__ When comparing with the other groups, I had the fastest reaction of .08 seconds and 3cm, and Collin had the "slowest" of .23 seconds and .27cm. The average was .16 seconds __**2B:**__ It is very likely that reaction times of people from the same age group vary since some people are trained to react to things quicker than others by playing sports, videos games, or other activities. It is also likely that once a person reaches a certain age, their senses deteriorate and they become less apt to react.

Average is 20
 * T1 || 22 ||
 * T2 || 20 ||
 * T3 || 18 ||

Average: 27
 * T1 || 38 ||
 * T2 || 27 ||
 * T3 || 26 ||

1A: Reactions should be slower once the subject becomes distracted. 2A: We found that the average reaction time when someone is distracted is actually slower when they are not. 2B: Things like talking on the phone, fighting with other passengers and eating might be enough to distract the average person.

Checking Up:

1A: Distractions will affect the person driving, because they have the ability to delay the senses of a person. 1B Driving when under the influence will inhibit your reaction time and is extremely dangerous to you and other people.





__**What do you think now?**__
Your senses such as sight, hearing, and feel usually are the most important in determining someones reaction time.

__**Why should you care?**__
Reaction times help us perform in our every day lives with things like driving and playing sports.

__**Chapter 1 Sec 2-9/14**__
What do you see?

I see a boy comparing footsteps to a little girl. Odd numbers on the doors. Kitty cat Physics room

What do you think?

I think the numbers of the measurements are different because of the size of the people.

I think they may have made a mistake, but it's really not that big of a deal since its such a small amount.

15 43

645

Random measuring-

106.5

Laptop-mete-33 Table-Mete-106.5 Water bottle- Cm-20 Ring stand-Meter-52cm Quarter- ruler-2.2

Uncertainty-5mm

17x12

1450

850x600

Chatper 1 Section 3

What do you see?

I see a bunch of people about to get into a car accident.

The safe amount of time between each car is about two seconds

- What factors affect the time you need to react to an emergency situation while driving? > 2. There were several ways we measured reaction time during this section. One of the tests that we conducted was where we had a subject with a watch time another person on how long it would take to switch your foot to the brake. Another test was when my partner and I both tested to see how far apart our times wree when we compared stopping stop watches. Lastly, we used a ruler marker with the formula: d=1/2at^2 to determine how much time it took to fall to the ground or into the subjects hands. The times of other people in our class ranged from .155 seconds to .23 seconds. > 4. Reaction time is very important when driving for many reason. For example you need to be aware and able to react to whats happening around you at any given time since accidents are very random. Needles to say, if you have a faster reaction time, you'll more apt to avoid a serious accident. > Ages: 16-19 > || Person 1 || 8 || .1277 || > || Person 2 || 10 || .1468 || > || Person 3 || 9 || .1355 || > || Person 4 || 13 || .1629 || > || Person 5 || 6 || .1101 || > || Person 6 || 15 || .1749 || > || Person 7 || 20 || .2020 || > || Person 8 || 15 || .1749 || > || Person 9 || 16 || .1807 || > || Person 10 || 12 || .1565 || > || Person 11 || 6 || .1101 || > || Person 12 || 18 || .1917 || > || Person 13 || 14 || .1690 || > || Person 14 || 10 || .1468 || > || Person 15 || 8 || .1277 || > || Person 16 || 9 || .1355 || > || Average || 11.8125 || .1533 || This graph represents people at a bar (ages vary from 27- 66) > || Person 1 || 18 || .1917 || > || Person 2 || 17 || .1863 || > || Person 3 || 20 || .2020 || > || Person 4 || 22 || .2119 || > || Person 5 || N/A* || N/A || > || Person 6 || 14 || .1690 || > || Person 7 || 17 || .1863 || > || Person 8 || 19 || .1969 || > || Person 9 || 20 || .2020 || > || Person 10 || 18 || .1917 || > || Average || 18.33 || .1930 || 2. The reaction times obtained from the guys on my paintball squad and from the people at the bar varied compared to those of the kids in our class. For example, the guys on my paintball squad were pretty close to those of the kids in our class. I found this surprising, since in paintball, you have to have great reactions and a very quick trigger finger. I guess this is just due to the age similarities. 4. Of course a race car driver would need to have a better reaction time than someone who is in a school zone. The race car driver is doing 18-200mph and has to navigate turns, avoid cars, and think of a way to win, when the person in the school zone is doing 20 and their only risk is they might bump into a kid. 5. Things like alcohol, talking on a cell phone and changing the radio can dramatically slow down your reaction time, which, in turn can cause for more accidents. 6. Some consequences of those driving with a slow reaction time, rather then quick, can face problems such as not being able to avoid accidents with other cars and even people crossing the street in front of them. Also, maybe the light changed as they were about to go through the intersection and they didn't react fast enough to stop at the light and instead went through it. Doing this can cause accidents and at the very minimum cause you to get a ticket. 7. Even though teenagers have a faster reaction time then older, more experienced drivers, their insurance costs more because they tend to be more reckless and drive at faster speeds which can cause accidents. Also, they are not nearly as experienced which can also cause problems. 8. Knowing your own reaction time can cause you to be a safer driver because then you can take the necessary precautions to avoid an accident. For example, you can stay at a distance behind the car in front of you where you know you will have time to stop if they get into an accident.
 * What do you think now?**
 * Some of the distractions we observed during the investigation were talking and texting on the phone, drinking and eating while on the phone, and also arguing with other passengers while trying to drive. These distractions are very significant and can seriously hammer someones time to be able to react to a situation. It is very important that someone must always be focused on the road, and not the things going on around them.
 * **Physics Essential Questions-**
 * 1. Reaction time is the amount of time it takes for someone to react to something, with or without distractions.
 * **Physics to Go-**
 * This graph represents people on my paintball squad.
 * || Distance caught on ruler (cm) || Reaction Time (s) ||
 * || Distance caught on ruler (cm) || Reaction time (sec) ||

**What do you see?**

 * A guy walking along the ruler with larger steps
 * A little girl taking smaller steps.
 * There is a geeky looking kid recording the info.
 * The kids are walking up the hallway and the numbers are getting larger.

**What do you think?**

 * No, they didn't make a mistake. One of them could have used a measuring device that isn't as precise as the other. Or, maybe they measured the wrong info of the object.
 * I think that one of the students was just more precise than the other.

**Investigate-**
2.
 * || Number of Strides || Distance of Stride (cm) || Total Distance (cm) ||
 * Trial 1 || 16 || 41 || 656 ||

5A). The measurements were usually within 100cm of each other. 5B). I think the main cause of mistaken readings may have been from people incorrectly measuring. 5C). Maybe everyone can take the same strides, which may improve the range of measurements. 6. The total distance of the course was 1319 cm (13.19 m). 7). No, none of the measurements were the same. They varied by 100cm 7B). The main reasons the measurements were different has to be the random error and difference in length. 7C). Another method of measuring could be to find out how big each tile in the hall way is and then find out how many tiles are in between the black strips of tape. Then you could multiply both those numbers and see how long the course is (you may have to switch the units around so it is in metric). Groups answers probably wouldn't vary that much because there really isn't a whole lot of error that could happen in this method. 7D). I think some of the possible values would be close to that of the values we got using the meter stick, as long as their weren't any errors with the meter stick. An example of value might be 13 meters 19 centimeters because that is what we got measuring the course with the meter stick. Not every group may get the same value because some groups may still make a systematical or random error. 7E). There will always be a difference in values due to the common variables and human error. 8A). One of the systemic errors we faced was starting a little to far from the beginning of the tile. This put or whole measurement out of whack and messed with our results. 8B). Usually our random error was about 1-4cm and with the meter stick it was about 1-5cm. 9A). This is a somewhat decent estimate since most college people weigh around 170-220IBS. 9B). This is a ridiculous estimate since the average male is near 6 feet. 13 feet is something for a giraffe. 9C). This is not a decent estimate since the average teacher works much less than 1480 minutes. 9D). This is not a good estimate because an average poodle weighs about 40 pounds maximum with most being between 20 and 30 pounds. 9E). This is not a good estimate since the average class size is around 27 cubic feet. 9F). This is a ridiculous estimate since the average school campus isn't even a half mile. 9G). You have to guess how big your truck is and how large the other truck is. Honestly, its not worth the risk of damaging your truck. 9H). Before you estimate if it can fit, you have to know which way it's on the motor home.

//__**Physics Talk, Checking Up-**__//
1. The difference between the two is that systematic errors are errors that can be corrected with calculations and back-ups. Random errors are pretty much un-avioidable since humans are not perfect and will always make a mistake. 2. There will never be a perfect reading from a human due to human errors. 3. To be completely random, the arrows must be spread out with no pattern or clustering.

__**Active Physics Plus-**__
1. +/- 10 cm = 49.9 m about 50.1 m (D=20cm) +/- 1 cm = 49.99 m about 50.01 m (D=2 cm) +/- 1 mm = 49.999 m about 50.001 (D=2mm) 2. speed= distance/time about t=distance/speed speed= 50 m/25 m= **2 m/s** t= 2cm/2 m/s = .2m/ 2m/s= .01 seconds. 3. Speed= d/t,,,,speed=1500 m/ 900 seconds= 1.666 m/s t=60cm/1.666m/s= .6 m/ 1.666 m/s= **.360 seconds** 4. It is possible since readings can't be too specific, and someone may have done it by a fraction of a MM.

__**What do you think now?**__

 * It is uncertain whether it's systematic or human error it is definitely an error. 21 feet is a huge difference.
 * There probably wasn't a mistake since one of the readings could have been rounded.

__**Essential Questions**__

 * What does it mean?
 * This type of error would be a random error. This is caused by the simple variables of human mistakes.
 * How do you know?
 * It is most likely that the jeweler rounded the nugget up to 1, since it's very unlikely to have an exact number like that.
 * Why do you believe?
 * I think that you cannot trust every reading that your classmates since some made mistakes and their data will reflect it.
 * Why should you care?
 * Everything is relative. You don't stop a fraction of a second fast enough, and you could wind up dead.

__**Physics to Go**__
A). It is best to use a centimeter ruler for the quarter and the water bottle. And it is best two use a meter stick for the table, laptop and ring stand. B). For each measurement there is a +/- 5 mm of uncertainty. 2A). It takes 16 strides to walk the length of the room and 11 strides to walk the width of the room. With an average stride of about 50 cm, the length of the room would be 800 cm x 550 cm. With a meter stick the size of the room is 950 cm x 880 cm. 3A). Me and my friend both estimated the same length of a pencil. We both estimated it would be about 8 inches. But, then when we estimated the height of a door, I estimated about 8 feet, but estimated it to be about 9 feet. 4A). The accuracy of label have to be very accurate since the FDA requires them to be near-precise. 6A). I do not think the estimate is reasonable. I doubt they would be able to get 2 glasses of soda. 6B). This estimate is reasonable. Considering the distance between Boston and NYC is less then 280 miles, I think it is plausible. The average SUV can get around 300 miles. 7A). In respect to relativity, being off by 1 meter when measuring your room is alot different then being off by one meter when measuring the distance between school and home. It's like being off by one mile when measuring the length of a town and measuring the distance between the earth and moon. 8A). The safe thing to do would be to go about 60 mph since there is a 5mph +/- on the limit. 8B). The passenger could use the formula, speed=distance/time and measure out a mile and see how long it took and then use the formula to find out the speed. 9A). You should not and COULD NOT get a ticket for being 1mph over the speed limit. The devices to measure the speed are not accurate nor reliable enough to be able to detect that.
 * || Length ||
 * Table Width || 106.5 cm ||
 * Water || 20 cm ||
 * Laptop || 33 cm ||
 * Ring Stand || 52 cm ||
 * Quarter || 2.2 cm ||

__**What do you see?**__

 * I see a car accident between 3 cars.
 * There is a rabbit on the side of the road.
 * The rabbit distracted the drivers.
 * The cartoon indicates the lady in the yellow car is still moving.

__**What do you think?**__

 * A safe following distance with your vehicle and the car in front you is the 2 second rule. This is where you pick an object and from when the vehicle in front of you crosses that object, you make sure you don't pass that object in 2 seconds.

__**Investigate**__ b. No, the automobiles are not the same size apart successive photos. The images are farther apart then they were at 30 mi/h. The car going 30 mi/h goes .5 miles in 1 hour. And the car that is going 45 mi/h goes .75 miles in 1 hour. c. I decided how far apart each of the x's would be by putting 60 spaces in between each of them. Same thing for the above. For 45 MPH I put 45 spaces and the one for 30 mi/h I put 30 spaces.

4A).



4B).

http://acp7schwarz.wikispaces.com/file/view/1.3_Question_4b.png/258387324/1.3_Question_4b.png 4c

4D).




 * 5**




 * 5b**




 * 5c**

7A). According to the graph on 5b (our most recent chart as of now) we walked 2.55 meters, which is 1.25 meters toward the motion sensor and 1.3 meters away from the motion sensor. B). It took the person walking 4.94 seconds to walk this distance. The difference between the finish and the start is 6.5 seconds minus 1.56 seconds which gives you 4.94 seconds. C). 1.25m/4.94 seconds= .253 m/s. D). My assumption would be that the position of the person that is walking twice as long would be twice as far from the original number. This makes sense because you are doubling the position from the first trial by the new one. 8A). If the person's reaction time is .5 seconds that means the car will have traveled 30 feet in those .5 seconds. I know this because if the car is going 60 feet per second that means it is going 30 feet in .5 seconds. B). If the person's reaction time is 1.5 seconds I can do the same things as in 8a to determine how far the car will travel. I know that the car is going 60 feet per second, so the car will travel 90 feet in 1.5 seconds. C). If the car is going 50 feet per second then the car will travel 25 feet. And if the person's reaction time is 1.5 seconds the car will travel 75 feet. D). If the car is going 70 second and the person's reaction time is .5 seconds, the car will travel 35 feet. And if the person's reaction time is 1.5 seconds the car will travel 105 feet. E). If the car is traveling at 40 feet per second and the driver has a reaction time of .5 seconds, to avoid hitting the car, the preceding car should travel at at least 20 feet per second to allow the person to stop just short. F). An automobile traveling at 60 feet per second travels about 4 car lengths per second if the average car length is 15 feet.


 * Physics Talk-**

Time= distance/Vavg Distance= time*velocity

1A).
 * Physics Plus-**

1b). 2A). 3B). 3A).

__**What do you think now?**__ __**Essential Questions-**__
 * A safe distance really depends on how fast, where you are on the road, and what terrain. It's usually good to just be conservative and be 3 seconds behind in the normal area.
 * You can find the answer by using the formula "Vavg= distance/timer. Also, you can do distance= time*Vavg. The numbers you plug in should be 3 seconds for time and your average velocity in units/second. And by solving this equation you could find your following distance.
 * What does it mean?
 * This means that the car is traveling 40 miles/hour. This means that in 2 hours the car could travel 80 miles.

__**Physics To Go**-__ 1A). In this strobe photo the car is moving at a constant speed. B). In this photo the car is moving at a constant speed but then speeds up quick and goes back to the constant speed. I know this because the car has the same spacing, then the spacing gets larger and then it goes back to the equal spacing. 2A).

B).

3). Distance= time*Vavg D= 350 ft/s * 20 seconds= **7000 feet** 4A). Vavg= distance/time Vavg=215 miles/ 4.5 hours= **47.777 miles per hour.** B). No, you do not know how fast they were going through Baltimore because maybe they were in traffic because they may have been in traffic. 5). Vavg= distance/time- Vavg= 15 miles/ .25 hours= **60 miles per hour.** 6A). In this graph the car is driving at a constant speed and then it comes to a stop B). In this graph the car is maintaining a constant speed going away and then comes to a stop. After it comes to a stop it maintains a constant speed going toward the object at a lesser velocity then when it was driving away from the object. C). In this graph the car is driving at a constant speed and then accelerates to a faster speed which it maintains. D). In this graph the car is continuing its acceleration without slowing down. 7A). The distance= time*Vavg distance= 25 m/s* .12 seconds= **3 meters.** B). The distance= time *Vavg--- distance= 16 m/s* .12 seconds= ** 1.92 meters .** This distance is a less distance then that of 25 m/s. This is because the car is going at a slower speed, which increases my reaction speed. C). The distacne= time*Vavg--distance= 25 m/s* .24 seconds= **6 meters.** 8A). Traffic experts can determine this time by using the formula distance= time*Vavg. You can do this by multiplying your speed of your car by 3 seconds and this distance you get should be the space you leave between the car in front of you and yourself. B). No, three seconds would not be quick enough on an interstate, which means the distance you travel after the car stops would be greater which may be able to cause an accident with another car. 9A. distance= time*Vavg ---distance= 100 ft/s * (1/3) second= 33.333333 feet. B). Yes, this is longer then the length of the classroom. 10A). distance= time*Vavg -- distance= .5 seconds* 88 feet/second= 44 feet. B). This space will fit 2 cars and almost 3. If there was one more foot in the space you can fit 3 cars. C).The distance= time*Vavg --distance= 43.8 feet/s* .5= 21. 9 feet. You can fit just one car in between the space. D). The distance= time*Vavg -distance= 132 feet/s *.5= 66 feet. This is 4.45 of a football field. I know this because 300 feet/ 66 feet= 4.45. E). At every one of these increasing speeds, the driver's reaction time is getting sharper and sharper. For example at 30 mph to 60 mph the person's reaction time doubles and from 30 mph to 90 mph, the person's reaction time triples.

SECTION 4:

-What do you see?

I see two cars, and one is speeding and going through the red light.

-What do you think? The Bus is heavier and may have to take a longer time to come to a complete stop. They are both accelerating though. They both will have the final velocity.

1a. I think that the farther the car gets down the ramp, the faster the car will go. b. The chart in which one of them does not move is the chart on the bottom right. A chart in which the more time goes by the farther the car goes is the chart on the top right.The chart in which the car travels at a constant speed is the car on the bottom left. And the chart in which the car travels fastest at the end is on the top left. c. In this graph the car will start off moving slowly down the ramp and at time goes on and the distance increases the faster the car will be going. 2a. b. The graphs from our prediction and that of the actual graph are very similar and there really aren't any differences. c. In the examples only A and B are tangent lines, but C is not. An example of a tangent line for C is: d. As time increases the slope will continue to increase because the car will continue to gain speed. e.
 * Investigate-**

3a.

b. Compared to 2e the prediction and the actual graph are pretty similar because they both start at 0 and gradually increase in velocity. The graph starts at (0,0) because when the car is at rest it is not moving and therefore has no velocity. c. The change in the slope as time increases will be equal because the car has a constant velocity. d. The acceleration of a car as it travels down the ramp is constant. e. acceleration= change in velocity/change in time =======> acceleration= .5-.35/1.60-1.35 =======> acceleration= .15/.25= .6 m/s^2.

4a. b. 5a. b. c. The slope of the d-t graph is negative when the car is going up the ramp and positive when the car is going down the ramp. This is because when the car is going up the ramp the car is losing speed, but when the car is going down the ramp it is gaining speed. d. The slope of the v-t graph is negative when the car is going up the ramp and positive when the car is going down the ramp, just like in the d-t graph. This is because when the car is going down the ramp the car is losing velocity and when the car is going up the ramp it is gaining velocity. e. The slope of the car going up the ramp in the d-t graph is -.325. This means the car has a negative acceleration of -.325 meters/second. And the slope of the car going down the ramp is .741. This means the car has a positive acceleration of .741. The slope of the car going down the ramp in the v-t graph is -3.22. This means the car has a negative acceleration of -3.22 meters/second. The car going down the ramp in the v-t graph has a slope of .85. This means the car has a positive acceleration of .85 meters/second. 6a. The d-t graph will look like this because as time went on the distance increased, but the slope of the line started decreasing because as the car went up the ramp the speed of the car will continue to decrease. b.The v-t graph will look like this because as the car goes up the ramp the velocity at first is fast but as time goes on the car's velocity will decrease because the car's speed is slowing down. 7a. b. The prediction of what the d-t graph would look like from 6a is very similar to what the actual d-t graph looked like. There really isn't any differences. However there is a minor difference in the prediction of what the v-t graph would look like (6b) and what the actual graph looked like. On our prediction we had the graph being a more steep decline compared to the actual graph where it is a more gradual decline. c. The slope of the d-t graph is pretty constant as it increases, but towards the end of the acceleration it starts to round off. The reason for this is because the car is starting to slow down and is about to turn around because it can no longer continue up the ramp. d. The slope of the v-t graph is also fairly constant at first, but then the slope starts to decrease to the point where it is a negative slope. The reason for this is because as time goes on the velocity of the car continues to decrease. e. 8a. In order to get this graph the motion sensor and the car would both need to be at the top of the ramp facing down to the bottom of the ramp. When you release the car you will get this graph because the car will gradually pick up speed as it continues down the ramp. b.In order to get this graph both the motion sensor and the car would need to be at the bottom of the ramp facing towards the top of the ramp. When you push the car up the ramp the car will start with a higher velocity, which will start to decline as it gets farther up the ramp to the point where it falls back down. This chart represents the area of the car going up the ramp to the point where the car starts to slow down. c. In order to get this chart the motion sensor and the car would be set up at the top of the ramp. In order to get this kind of line the car would need to increase its speed down the ramp. You know this because as time goes on in this chart the velocity of the car is also increasing. d. In order to get this graph the car could be at the bottom of the ramp, but the motion sensor will be at the top of the ramp. When the car is pushed up the ramp towards the motion sensor you should get this graph because the car's velocity will decrease as time goes on. 9a. (This chart is not in this section). 10a.

b. From 0 seconds to 2.9 seconds the velocity is changing the most. c. From 4.2 seconds to 13.3 seconds the velocity is changing the least. d. The acceleration is greatest at 2 seconds because the change of 44 ft/s and 0 f/s is 44. But, the acceleration is the least at both 4.2 seconds and 8.7 seconds. At both of these time periods the change in velocity is 14 ft/s, meanwhile everywhere else on the chart (except for at 2 seconds) the change in velocity is 15 seconds. 12a. acceleration= change in velocity/ change in time ========> acceleration = 59 feet per sec- 44 feet per sec/ .9 seconds= 16.667 ft/s^2. Yes, I got the value of 16 ft/s for every second. b. c. The steepest incline (greatest slope) according to the chart is the same as what I predicted according to the velocity-time graph from question 10a. Both indicate the steepest incline is at 2 seconds.

- Velocity is how fast an object is going and in what direction, therefore velocity is a **vector** quantity. - Vector means to be both size and direction. - The distinction of speed and velocity is important when a change in direction happens because when a car is going around a curve at a constant 15 m/s the car is still accelerating because there is a change in direction. - The three ways you can increase a cars velocity are: - Instead of using deceleration a person should use the terms **positive acceleration** or **negative acceleration** to avoid confusion. - When an object has mass (speed) but no direction the term used to describe it is a scalar quantity. - acceleration= change in velocity / change in time. - The unit for using acceleration is m/s^2 or (m/s)s. - Some other key formulas are: - To show acceleration by graphing you would need distance on the y-axis and time on the x-axis. You would then need to put in the tangent line in and find the slope of the graph. That line is the acceleration. 1). Correct, because acceleration is equal to change in velocity / change in time, as long as the velocity is not changing then the acceleration would be zero.
 * Physics Talk-**
 * -** Galileo was the person who invented the idea of acceleration. He did this by rolling balls down an incline and used things such as a water clock to help him track the time that elapsed. He presented the idea that acceleration is equal to the change in velocity over the change in time.
 * Increase the speed (speed up)
 * Decrease the speed (slow down)
 * Change the direction of a car (turn)
 * Change in velocity= acceleration * time
 * time= change in velocity / time
 * Motion Equations-**
 * Homework 10/17- Average Acceleration/ Displacement With Constant Uniform Acceleration/ Velocity and Displacement with Uniform Acceleration:**
 * Part 1:**
 * Part 2:**
 * Part 3:**
 * Physics to Go:**

2). Yes, when a ball reaches its terminal velocity in the air, its acceleration is zero and it's velocity is nonzero.

3). Yes because we know that V= acceleration * time. If the object has the same acceleration there is no amount of time that you can multiply by to get a different velocity, which proves the idea wrong. Say two objects have the same acceleration of 5 m/s^2 but one it is over 1 second, but for the other object it is over 2 seconds time, you will get different velocities.

4). A car going at a constant speed could infact pass the accelerating ones since, they would just be starting out at accelerating.

5). Yes, the constant speed out beat the accelerating cars since the constant could be going faster than the one accelerating.

6). It does matter whether or not you use vector, since a vector is a measurement of speed in a certain direction.

7A). V= acceleration * time. Velocity= .0005556 mi/second x 5 seconds= .00278 mps. This is only for 5 seconds, we need to get the answer for 2 minutes. So, to get this we know that 5 seconds is 1/5 of a minute, which is 1/10 of 2 minutes. So, if you multiply .00278 by 100 you will get our answer of .278 mi/second.

7B). distance= 1/2 (Vinitial + Vfinal) * change in time > distance= 1/2 (0+.278)*120 seconds= 16.68 meters.

8A). acceleration= change in velocity/ change in time > acceleration= 75 m/s / 9 seconds= 8.33 m/s^2.

8B). Vavg= acceleration * time > Vavg= 8.333 m/s^2 * 9 seconds= 74.997 m/s.

8C). distance= 1/2 (Vi+Vf) * time > distance= 1/2 (74.997+0)*9= 337.49 meters.

8D). The second cars acceleration would be greater then that of the first car. The second cars average speed during the acceleration would be greater then that of the first car. And the distance traveled would be less then that of the first car.

9A). acceleration= change in velocity/change in time > acceleration= .6-4.5/1.3= -3 m/s^2.

9B). distance= 1/2 (Vi+Vf)*time > distance= 1/2 (5.1)*1.3= 3.315 meters.

9C). Vavg= acceleration * time > Vavg= -3 * 1.1= -3.3 m/s.

9D). The first trial would get her from second to third the fastest. 10A). The approximate top speed reached by the object falling was about 11 m/s.

10B). acceleration= change in velocity/change in time > acceleration= 9/7.5= 1.2 m/s^2. The acceleration of gravity on this planet is 1.2 m/s^2.

10C). If the astronaut dropped the object from a higher point, then the acceleration would not change, but the objects final velocity would increase.

11A). SEE Graph D

11B). SEE Graph C

11C). SEE Graph B

11D). SEE Graph A 11E). SEE Graph F

11F). SEE Graph E

12A. B through E

12B). A through C

12C). D through E

12D). E through H

12E). 0

12F). 0 meters

__**Section 5**__

__**What do you see?**__

A moose about to get hit

__**What do you think?**__

Speed

Reaction time

Condition of road

Area

HOMEWORK~

__**What do you think now?**__ -Your initial velocity -Speed -Breaking conditions

__**Section 6-**__
__**LO-Investigate the factors of the stopping distances of the "stop and go" zones**__

__**What do you see?**__

__**-**__ I see an intersection with the light on red(right) and yellow (front) -There are many cars skidding and -Cars tried to speed up when they saw the yellow light.

__**What do you think? -**__

-I think it would enable people to try and beat it out -If people knew exactly when the lights started and stopped, then they would try and brake them. -People could try and bust right through the light and wind up going into the other lane.

__**Investigate-**__ 3A). Yes the car is in the "go zone" 3B). Yes, the car is still in the "go zone" 3C). YEs 3D). It could be in the go zone, but they are not sure. 4A). Automobile E is in the stop zone 4B). No, it is in the "go zone" 4C).

5A).

5B).
 * ** Variable ** || ** Change ** ||  || ** Predicted effect of change **
 * on GO ZONE ** || ** Actual effect of change **
 * on GO ZONE ** ||
 * ty || yellow-light time || increase ty || The go zone will increase. ||  ||
 * ||  || decrease ty || The go zone will decrease. ||   ||
 * tr || response time || increase tr || The go zone will increase. ||  ||
 * ||  || decrease tr || The go zone will decrease. ||   ||
 * v || speed limit || increase v || The go zone will increase. ||  ||
 * ||  || decrease v || The go zone will decrease. ||   ||
 * a || negative acceleration || increase a || The go zone will decrease. ||  ||
 * ||  || decrease a || The go zone will decrease. ||   ||
 * w || width of intersection || increase w || The go zone will increase. ||  ||
 * ||  || decrease w || The go zone will decrease. ||   ||

6A). The "GO zone" would be 3 at 53 meters 6B). The "Go zone" would be 3.5 at 65 meters 6C). Yes it would because as the yellow signal period increases, then the amount of time (distance) the person has to get to and through the intersection safely. 6D). Changing the yellow-light would make drivers less able to try and speed up and bust right through the intersection.

8A. (DONE IN GROUP) yellow light time: Yes this makes sense to us. human reaction time: This does make sense to us, although our prediction was off. We predicted that the go zone will increase, but in fact it did not change. negative acceleration: This does not make sense to us because as the car slows down, then why doesn't the go zone decrease because the car isn't driving fast enough to make the light. width of intersection: This does not make sense to use either because the width of the intersection should mean that the wider the road the more cars get through, not less of a go zone. 8B. Our prediction for yellow-light time in relation to the go zone is right on, but all of the other predictions were off. 8C. Go zone is the velocity of the car times the yellow light time subtracted by the width of intersection. 9D. These appear, because they are the most important to the equation. 9E. These two factors do not appear in the equation for the go zone because they have no effect on the go zone. They do not have an effect on the go zone because they do not have any effect on the go zone. When you are in the go zone, the reaction time has no effect on driving with a constant speed.

9A. "STOP Zone"= (speed of car time the human response time plus the speed of vehicle^2 ) divided by the (2 times negative acceleration rate). 9B. These factors only apply to the "GO zone" 9C. The yellow light factors do not apply to the other variables.

__**Section 6: Part B-**__
1A. Car A- Stop Car B- Go Car C- Go Car D- Stop 2A. Car E- Stop Car F- Stop Car H- Stop if possible Car G- Go 3A. Car J- Stop Car L- Stop Car M- Go Car K- Go 4A. Intersection number 2 has a greater "GO zone" then the other two intersections, although the "GO zone" also runs into the STOP ZONE so it depends on what the other cars are doing. Also, Intersection II is the only intersection where the GO and STOP ZONES overlap. 4B. In this situation, you should probably just keep on going, so you don't get hit by another car. 4C. It's really up to the driver, but you could go if you wanted to.

6a.

B- Width going north to south on Piermont is 40 feet Widths going east to west on Kinderkamack 30 feet c. I used these numbers because then there is no dilemma zone making the intersection especially safe. In this case both roads have overlap zones and no dilemma zones, so these numbers would work fine.
 * **Variables** || **Crossing Piermont** || **Crossing Kinderkamack** ||
 * Yellow Light Time (Ty) || 3 seconds || 3 seconds ||
 * Human Response Time (Tr) || .20 seconds || .20 seconds ||
 * Velocity of a Car (v) || 35 mph or 15.64 m/s || 35 mph or 15.64 m/s ||
 * Acceleration of Car (a) || 4.9 m/s^2 || 4.9 m/s^2 ||
 * Width of Road (w) || 40 feet or 12.19 m || 30 feet or 9.14 m ||
 * GO ZONE || 34.73 m || 37.78 m ||
 * STOP ZONE || 28.0882 m || 24.0882 m ||
 * Safe/Not Safe || Overlap Zone || Overlap Zone ||

1A). "GO Zone"= (15 meter a second) times (4 seconds)-15 meters= **45 meters** 1B). STOP ZONE= (15 m/s)* (1 second) + (15 m/s)^2 / 2(5 m/s/s) = **37.5 meters** 2A). GO ZONE= (30 m/s)*(4 seconds)- 15 meters= **105 meters** STOP ZONE= (30 m/s)* (1 second) + (30 m/s)^2 / 2(5 m/s/s) = **120 meters** ***This could be dangerous because by speeding there is now a dilemma zone.**
 * Physics To Go-**
 * 2B).**
 * GO ZONE= (10 m/s)*(4 seconds)- 15 meters=** 25 meters
 * STOP ZONE= (10 m/s)* (1 second) + (10 m/s)^2 / 2(5 m/s/s) =**20 meters
 * By lowering the speed limit, the only effect they are making is decreasing the size of the GO and STOP ZONE'S. The intersection will still be a dilemma free zone because it is an overlap zone.**
 * 3.**
 * A person listening to loud music, which increases their reaction time does not increase the GO ZONE because while you are driving through an intersection, your reaction time doesn't matter because you aren't stopping. However, the higher reaction time effects the STOP ZONE because you need your reaction time to move your foot from the gas to the break and that increased time also increases the STOP ZONE.**
 * 4.**
 * No, this will not effect the GO ZONE and STOP ZONE at a yellow light because it is not one of the factors that effect it. The only factors that have an influence on the GO ZONE or the STOP ZONE are yellow light time, human reaction time, velocity of the car, width of the road and the acceleration of the car.**
 * 5.**
 * The reason for this is because perhaps up the road there is another light and the time that the light does not turn green is to keep traffic flowing normally, without traffic. The time in between red and green lights could let the traffic up the road clear before more traffic comes.**
 * 6.**
 * Traffic engineers probably don't use this now because even though the light was yellow, cars can still go through the light. It might make more sense if they did this countdown to the red light to help drivers judge the yellow light time. The countdown effects the stop and go zones because people might speed up their car to try and force their way through the light, which in turn could decrease the size of the go zone and stop zone as well as cause a dilemma zone, which might make the intersection unsafe.**
 * 7.**
 * A-**
 * GO: 48 m**
 * STOP: 52.57 m**
 * This is unsafe because there is a dilemma zone of 4.57 m.**
 * B-**
 * GO: 72 m**
 * STOP: 52.57 m**
 * This area is a safe zone because there is an overlap zone that is 19.43 m.**
 * C-**
 * GO: 48 m**
 * STOP: 48.57 m**
 * This area is unsafe because there is a slight dilemma zone that is .57 meters long.**
 * D-**
 * GO: 48 m**
 * STOP: 64.57 m**
 * This area is unsafe because there is a dilemma zone that is 16.57 meters long.**
 * E-**
 * GO: 40.5 m**
 * STOP: 34.07 m**
 * This area is safe because there is an overlap zone that is 6.43 meters long.**
 * 8). Yes, because then there is no doubt in people's minds if they would be able to make the yellow light or not. This would probably count down on the number of lights and tickets that might occur at intersections.**
 * 9.**
 * --I think you should let me use your car because during this section I have learned everything I need to know about intersections with a yellow light. I have learned that if you are in a certain area called a go zone, then it would be safe for me to make it through the yellow light. Contrary to this though, if you are in a stop zone, it is unsafe to make it through the light and you should stop. The area in between the two could either be a dilemma zone or overlap zone. If it is a dilemma zone, then you must make a decision based on the other cars behind you and in front of you. This area is dangerous because either way you go, it is not guaranteed if you could stop at the light in time or guaranteed that you can make it through the light in time. But, the dilemma zone is a rare occurrence because most intersections are overlap zones. In this area the driver could either chose to go or stop and it would be safe either way.**

__Light time, width of intersection, speed of the car, negative acceleration, reaction time**__

__**STOP ZONE= VTr + V^2/2a**__
__**---**__

__**Section 7**__
__**-What do you see? -**__ A car is driving around the side of a mountain. -What do you know?- The person is taking the turns way too hard and is in danger of falling off the mountain.

Investigate:

1A). I think that it would take path B since the car was rotating around a center and the string was making the car go in a circle, which once it was released, it would Equations for friction:

**How are these equations used when driving?**

 * Circulation motion is used when driving because in order to move any direction there needs to be a force applied. If there is no force applied, the car will keep moving straight. This is Newton's First Law of Motion.

**Investigate-**
1a. B, because as you take your finger off the string the car will not have any force making it go in the circle anymore. So, without the force making it go in the circle, the car will go straight. 2a. The direction of force being applied on the car is pulling it towards the center. b. When the string is released, the car continues traveling in a straight line. 3a.

**FOR A LARGE WASHER ON A SMOOTH SURFACE**
4a. It is 19 cm to the center of the turn table. 6a. 17.29 seconds for 10 revolutions. b. 10 revolutions/17.29 seconds= x revolutions/ 60 seconds 17.29x=600 x= 34.7 revolutions per minute (rpm) c. 34.7 revolutions/ 60 seconds= x revolutions/ 1 second 60x=34.7 x= .578 revolutions per second (rps) d. This is a better technique because this way you get a wider field of measurements and find the average instead of just using one time. By doing it the way we are we are getting a more reliable time. e. The turntable is moving at .578 revolutions per second (rps). 7. The circumference of the circle is equal to 2(pi)(r) So, c= 2(3.14)(19)=119.32 cm a. Speed= distance/time Speed= 1.1932 m/ 1.729 seconds Speed= .69 m/s

**FOR A LARGE WASHER ON SANDPAPER**
4a. It is 19 cm to the center of the turntable. 6a. 10.90 seconds for 10 revolutions. b. 10 revolutions/10.90 seconds= x revolutions/ 60 seconds 10.90x=600 x= 55.04 revolutions per minute (rpm) c. 55.04 revolutions/ 60 seconds= x revolutions/ 1 second 60x=55.04 x= .917 revolutions per second (rps) d. This is a better technique because this way you get a wider field of measurements and find the average instead of just using one time. By doing it the way we are we are getting a more reliable time. e. The turntable is moving at .917 revolutions per second (rps). 7a. Speed= distance/time Speed= 1.1932 m/ .917 seconds Speed= 1.3 m/s

8a. The effect that sandpaper will have on the washer is that the washer will have better traction and therefore will be able to stay on the turntable longer. 9a. The smaller the radius is, then the geater the safe speed of the car will be. 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
 * 19 cm ||  ||   ||   ||   ||   ||   ||
 * 10 cm ||  ||   ||   ||   ||   ||   ||
 * 5 cm ||  ||   ||   ||   ||   ||   ||