Chapter+One


 * Section 1**


 * Reaction Time Lab**

Trial 1: 1.02 s Trial 2: 0.58 s Trial 3: .59 s Trial 4: .54 s Trial 5: .51 s
 * From Gas to brake:**
 * Average: .648**

Trial 1: .39s Trial 2: .24 s Trial 3: .14 s Trial 4: .04 s Trial 5: .13 s Trial 6: .13
 * Method A: Starting and Stopping Stopwatches**
 * Average: .17s**

Trial 1: 38cm Trial 2: 32cm Trial 3: 35cm Trial 4: 20cm Trial 5: 33cm Trial 6: 28cm
 * Method B: Meter Stick**
 * Average: 31cm**

Trial 1: 69cm Trial 2: 46cm Trial 3: 45cm Trial 4: 30cm Trial 5: 77cm Trial 6: 63cm
 * Method C: Meter stick while texting**
 * Average: 53.67cm**


 * Reading: Physics Talk**
 * **Reaction time in the car can be life or death**
 * In the experiment, we knew we would have to react, so we reacted at our best.
 * Slower reaction time when distracted, but was still expecting it
 * Sneezing is a distraction you can't avoid.
 * Drugs and alcohol are illegal to have while driving (duh)
 * Some medicines, even though most don't know it, are illegal to drive after taking
 * There are countless other factors to reaction time such as age, gender, practice etc.

Questions:

1. Distractions can affect reaction time because the driver doesn't have all his focus on the road, which can lead to him not thinking of what he is doing and not react to an emergency fast enough.

2. Drugs are illegal when driving because it can affect motor skills, thought processes, reaction times, and in some cases, vision. Alcohol depletes motor skills and impairs judgement. Some medicines such as cold or seasonal allergy medicines can cause the user to become drowsy, which can lead to the driver falling asleep at the wheel or making bad choices.

3. Three factors that can affect reaction time are age, gender, and practice.


 * Class Discussion**


 * Cell Phone part, not very distracting
 * Knew that the ruler was coming down, improved reaction time
 * Improvements: longer in time, blindfold so they don't see ruler, drop it in different places, blindfold to see the dropper's reaction
 * Red Light/Green Light: did slow down reaction (.238s to .389s)
 * Then with cell phone, it went up .456s
 * Other driving distractions: eating, gps voice, speedometer, kids, friends, rubbernecking, radio,
 * Driving under influence
 * Driving tired (focused on a spot in the road like a zombie.)
 * Old people more cautious, move slower (very slow)
 * Bad hearing
 * Hearing: can't hear horn, ambulance/cop siren.


 * Conclusion:**

The experiment that we preformed was flawed in many ways. The main reason is that the student was expecting that he had to react, this means in a real life situation, the reaction time would be longer. Even with distractions added to the situation, the student is still expecting to have to react. If the driver is surprised and then had to react, the results would end up a lot differently. The average response with the meter stick was 31 cm, while the response while distracted was near double at 53.67. If the factor of surprise was added, along with radio and passengers, the reaction time would be significantly longer.


 * Catching the paper**
 * It was difficult to catch the paper because the paper would come down, and the length of the paper was a lot shorter than the meter stick, which had an average reaction time of 31 cm.**

Control: .28s Distracted: .39s
 * Reaction Time Test:**

So far, this experiment has had the least factors involved, compared to Methods A and B. This test involved a student clicking the screen as soon as they see the dot change colors. Despite the simplicity, there are some faults with the experiment. One factor that can affect the reaction time was actually the size of the dot. The dot on the screen was actually quite small compared to the the black window it is contained in. It is hard to see the difference because as you look at it, you start to see the black more than the actual dot, so when it does change, it takes a second for it to register. This was proven correct in the actual program as the last dot change involves the dot becoming the size of the entire, which increased the reaction time by up to .1s. However, when preforming this reaction test while distracted is a completely different story. During the distracted test, Mr. Vannucci had us divert our attention, and eyes, to him. This made us look away from the screen, during which time the dot may change. The comparison in average has a difference of .11s. This is exactly the situation a driver would experience when the driver is texting while driving. The eyes are off the road, which in the case of a possible collision, would end up with the collision occurring because every split second counts. This, along with moving the foot from gas to break, along with the breaking distance can result in a stopping time of over a second and a half.
 * Write Up:**

3. It is quite difficult to catch the paper with the middle and index fingers, mostly because the middle and index fingers move very slowly. That coupled with the fast movement of the paper make it quite difficult.
 * Page 19**
 * A.** Explain why it is so difficult to catch the paper. Repeat the paper test, letting people catch it with their index finger and thumb.

It is significantly easier to catch the paper with the index and thumb because the index finger has a faster up and down motion than side to side motion. This however doesn't make it too easy to catch it. For someone with an average reaction time of .28, it is quite difficult to catch a 15mm piece of paper. We did a similar experiment in which a meter stick was dropped and the average number it was caught at was 31mm, which is double the length of the paper.
 * B.** Explain why catching the paper with the thumb and index finger may have been easier than catching the paper with the index and middle finger. Try to include measurements in your answer, such as length of paper, time for paper to fall, and average reaction time.

There is a range of reaction times during these experiments because not all the time the person being tested is 100% focused, but the range for reaction time is usually .25s-.34s.
 * C.** Is there a range of values for your reaction times? Explain your answer.

There might be a small decrease in reaction time, but this would be very small changes because reaction can't be changed at will. Someone can't choose to react faster, they can only react fastest at one speed.
 * D.** How would your reaction time change after repeating the same experiment several times? Why?

//__**Section 2**__//

1. It is obvious if they are both measuring the same object, that one is far off than the actual length.

2. If there is a .1cm difference between the two measurements, than I don't think they made a mistake, I think that they interpreted the data differently.

Preparing For the Chapter Challenge: 9. I don't think that 31 mph should be a speed at which a ticket should be given. Drivers usually fluctuate between different speeds, usually +/- 3mph of the speed limit. It is hard to keep it on the dot, but you still don't want to go too slow. Therefore, I believe that 31, or even 35 would be a reasonable speed.

Uncertainty- factors that can affect the measurement of something

Error doesn't indicate if it can be fixed or not.

Types of uncertainty:

Which was Which

Checking Up

1. Explain the difference between systematic and random errors. Systematic errors are errors that can be easily fixed through small calculations. An example would be 10 m compared to 10 yds. Random errors are errors are errors that can't be fixed with math.

2. Explain why there is always uncertainty in a measurement. In the instance where you are measuring a hallway, there is always interpretations of lengths, such as being in the middle of 1 and 2 cm, one may say it is a quarter, or a half.

3. What would the positions of the arrows on a target need to be to illustrate measurements that are neither accurate nor precise? The arrows would need to be a bit scattered on the target, no consistency on the target.

8. A. Measuring the hallways, I didn't have any systematic errors. B. I would guess we made maybe 5 errors per method. Some errors that might have happened might have been measuring one length at an angle (less vertical, more horizontal measured, not flush with the wall) 9. A. Yes, good estimate B. No, bad estimate C. No D. Yes E. Yes F. Yes G. No H. You would need to estimate the width of the bridge in order to see if it is wide enough. I. Can't be determined because it is unknown how tall the overpass is and how tall the bike and motor home is.

//__**Section 3**__//

1. A.

2. A.

C. I placed them this far apart because they are a mile between each other, meaning it is two miles from start to finish.

3. A. I believe that C is going the slowest because there is the least room between cars, and A is going the fastest because there is the most room.

B. Each car is going at a consistent speed because there the cars are equidistant.

4. A.

B.





C.





D.





5. A.





B. The trend of lines are similar is similar, however when it switched from walking towards to away, the prediction had a sharper corner at around 4 seconds.

6. A.



Slow:

Fast:



B. It might be difficult to determine what the labels would be if they weren't there, but one could assume that the bottom one is time.

7.

A. In my most recent trial, I walked about 4.2 m.

B. It took me about 5 seconds to move about two meters in the slow trial, and in the fast trial, it took me about 1.8 seconds to move 2.2 meters.

C. I was walking about 1.2 meters per second in my fast trial and I was walking about .4 meters per second in my slow trial.

D. To predict how far the walker would go after walking twice the time, you simply need to take the distance, and multiply by two, which in our case would equal 4.4 m, but this is only if the walker was walking at a consistent pace.

8. A. 30 ft

B. 90 ft

C. 25 ft

D. 75 ft

E. They should be at least 20 feet away to avoid rear ending the car in front of him/her.

F. Four car lengths

When there is no motion, the line would be mostly still, not moving on an upward curve, or a downward curve, similar to graph B. If Carly had started to move away from the motion sensor, then the line would have gone up. But since Carly had been staying still, it was more similar to A.

PTG 6-7

1. A. The car is going at a constant, consistent speed.

B. The car is going consistent, speeds up, then slows down.

2. T= car A. T T T T T T T T T

B. T T T T T T T T

3. 7,000 Feet.

4. A. The salesperson's average speed was about 47.7 repeating miles per hour.

B. She was going some where around 47 mph, add or subtract 10 mph, we know this because her average speed was 47mph so her speed needs to be somewhere around there.

5. The biker would need to maintain a speed of at least 20 miles per hour in order to make it to the park in under 15 minutes.

6. A. The car was driving at a very steady speed, then came to a sudden stop.

B. The car accelerated very fast, stopped suddenly, then went in reverse back to the starting point.

C. The car was going very slow, then picked up speed suddenly.

D. The car was gradually gaining speed as time went on.

7.

A. With a reaction time of approximately .2 seconds, my car would move about 5 meters.

B. With a .2 second reaction time, I would travel 3.2 meters in that time, which is 36% slower than A.

C. If I was drowsy and my reaction time doubled, that means my reaction distance doubled, making it 10 meters in that time.

NOTES: Average speed eqn= toal distance/toal time= d/t

V= d/t

Velocity - v - m/s Distance - d - meters time - t - s

Speed is a scalar. HAS NO DIRECTION. Force is an example of a vector Velocity is a Vector quantity. Has both direction and size


 * __//Section 4//__**


 * __//Investigation//__**

1. A. I predict that as time goes on, the cart's velocity will increase, meaning the first half of the distance would take longer to complete than the second half of the distance.

B. The bottom right graph is the graph which has no velocity and isn't moving. The bottom left graph is the one that travels at a consistent speed. In the top right graph, the speed is fast at the beginning and slower at the end. The top right graph, the speed increases.

C. I predict that the graph for the cart will start off slow and increase speed as it goes down the track. 2.

A. Actual

Prediction

B. Our prediction and actual graphs were very similar. In the first half, it was traveling at a slow velocity, then accelerated in the second half of the track due to gravity.

C. Examples A and B are tangent lines. Example C is not a tangent line because it passes through the curve instead of touching a single point.

D. As time increases, so does the slope. This means that the cart's velocity is increasing, covering more distance in less time.

E. We predicted the graph would look like this because we know the velocity increases over time. The line starts as being not very steep but as time goes on and the velocity increases the slope gets steeper.

3. A. B. Our prediction was that as time goes on, the velocity increases because of the gravity. It did however differ from our prediction because it took a few seconds for gravity to start to pull on the cart. Graphs start at 0, 0 because it shows the most amount of variables and gives perspective of scale.

C. As time increases, the slope of the graph mostly stays consistent, except for the beginning when it had a fast start, then leveled out at a consistent slope.

D. As the cart goes down the ramp, the acceleration increases.

E. .6mps - .3mps/ 1 s = .3 m/s2 The acceleration of the cart is .3 meters per second every second.

4.

A.

B.

5.

A.



B. For our predictions about the distance graph in 4B, the position was actually more gradual than expected. In our prediction, we predicted that the cart would move at a fast velocity to

C. The slope of the d/t graph stays the same and then slows down as it gets towards the bottom.

D. The slope decreases as the cart moves away from the sensor, then increases as it moves towards it back down the ramp.

E. .1 m/s@ 1 second and -.6m/s@ 3 second .5/2= .25 m/s/s

6.

A.

B.

7.

A. B. Our predictions in steps 6A and 6B were very similar to the graphs in 7B. They both had the same shaped lines but the intervals on the x and y axis were very different. The intervals on the predictions were a lot larger then the actual intervals. C. The slope increased slowly over time. D. The slope of the line drastically increases and then gradually decreases as the cart reach the top of the rail and the line went down towards the bottom. E. 8.
 * a= change in velocity/ time.** 80/1= 80. The acceleration is 80 m/s^2.

A. The motion sensor is at the bottom of the track and the cart is pushed up the track. The cart gradually increases velocity at a constant rate.

B.

A motion detector of this cart that could produce this graph would have to be acceleration. The cart moves on the incline, as the cart starts reaching the bottom, there happens to be friction causing the cart to come to a halt. The motion detector is placed at the top of the incline.

C. A motion detector of this cart that could produce this graph would have to be constant velocity. The cart is resting on a frictionless, horizontal plane. When the cart is given a slight push, it moves with constant velocity. The motion detector is placed at the start of where the cart is pushed.

D. A motion detector of this cart that could produce this graph would have to be velocity that is consistently losing speed. The cart is at the bottom of the incline and its given a slight push towards the top. It is losing speed. The motion detector is placed at the bottom of the incline.

11.

A.



The intervals on the y-axis are going by tens. The intervals on the x-axis are going by by twos.



B. During the 0.0s to 2.0s time interval, the velocity is changing the most.

C. The velocity is changing the least during the 6.6s and 8.7s, and during the 2.9 and 4.2 interval.

D. The greatest acceleration is 22 ft/s^2 that occurs in the 0.0s to 2.0s time interval. The acceleration that is the least is 6.25 ft/s^2 that occurs in the 10.9s to 13.3s time interval.

12.

A.

I did get the value around 16f/s/s.

B.

C. On graph 11a, the acceleration is greatest from 0s to 2s. The greatest slope also at this point, indicating a clear relation between velocity and acceleration.

10/2/11
 * Notes:**

Acceleration: Change in velocity over time

Velocity: how fast something goes in a certain direction.

Vector Quality: Something with size (magnitude) and direction

Something that is accelerating

10/3/11
 * __//Checking Up//__**

1. Give the equation for acceleration in words and in symbols Acceleration= velocity/time

2. What is an SI unit for measuring acceleration in words and symbols. 5.4 meters per second every second 5.4 m/s2

3. What is the difference between a vector and scalar quantity? A vector quantity has magnitude and direction, while a scalar quantity has magnitude, but no direction.

4. Can't sketch a graph on a computer, but a distance/time for consistent speed graph would look like a straight line going at an angle with no curve. A distance/time graph for constant acceleration would look like a bow shape with the curve either pointing to the bottom or the top of the graph.

5. What does the slope of a velocity/time graph represent? The slope of a velocity/time graph represents the acceleration of an object over time.

10/4/11

WHY

Consistent Velocity: The distance at which the object is traveling is at a consistent rate, so the slope is constant and unchanging.

Consistent Acceleration: The velocity is constantly increasing, so the velocity moves up on the graph faster than time moves right.

10/4/11

Moving Man

A. For graph A,

PTG

1. Yes, it will move consistently at 25mph

2. There can be an example where something can accelerate without velocity, as when a ball is thrown into the air, but then goes from traveling up, to going down because of gravity, the moment where there is no motion.

3. They probably will not have the same velocity because they can have two different instant velocities at the start of the acceleration.

4. They might have the same velocity at that moment, but the acceleration is probably not the same. It is possible for two cars to have the same velocity at a certain moment, but over time one will travel faster.

5.

6.

7. A. 2 min x 60 sec = 120 sec. 120 sec / 5 seconds = 24 intervals of acceleration by 2mph. 24 intervals x 2mph = 48 MPH as final speed. Avg. Vel. = 48-0/2 Average Velocity is 24. B. d= 24(1/30h)

Group 1.Benedict Like: Has the definitions, used the white board, knows the topic well. Don't Like: Needs more graphics or pictures, less text. A lot less text. How to improve: less text, make more interesting What I would copy: the large amount of definitions and such.
 * __//Mini Chapter Challenge://__**

Group 2. Horn Like: They know the slides Dislike: no pictures, not appealing, bland slides, less text Improve: Put pictures in, less text Copy: Not sure, just pure information

Group 3. Van-pelt Like. Knows topic well, Applies each section to each scenario. Dislike. Perfect, none Improve. Perfect, none Copy. Their format for presenting the information.