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Nel's Physics Journal

January 23, 2010
12:22
Journal 1/22
» ‎ Nel's Physics Journal

1. Identify what is it you are solving for such as the velocity.
2. Take direction into consideration when solving.
3. Remember that when momentum is constant, the final momentum will always be the same as the initial momentum.

-

1. No questions.

-

1. The problem is not impossible, just remember what you are looking for and take directions into consideration and you'll be fine.

[late due to not bringing notes home and hyperlinks not working]
January 11, 2010
21:41
Homework 1/11
» ‎ Nel's Physics Journal

B) System and process where money is constant is the upper right box. The amount of money does not change, that is how I know it is the constant. The constant is a quantity that doesn't change over time.

C) System and process where money is conserved is the second process. Cash changes from Chris to the lunch vendor. Conserve means that a quantity changes from one to another however the quantity does not dissipate.
January 07, 2010
9:00
Homework 1/5
» ‎ Nel's Physics Journal

1. The relationship between the magnitude of the acceleration and the speed of an object's distance is that the further the distance, the distance between each point is larger and the acceleration moves towards the center.

2. The relationship between the magnitude of the acceleration and the radius is that the larger the radius, the smaller the acceleration.

3. A= v2/r
2 m/s2 = 4/r
Radius = 8 meters.
December 20, 2009
20:24
Journal 12/18 revised
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1. Jon draws two force diagrams to represent two different objects of interest which are the forces acting upon the ball and the forces that act upon Chris. Yes, two force diagrams are needed because we need to find FnetY, which is the accumulative forces in the Y direction.

2. Yes the calculation will produce the correct mass of Chris because when we find the ball's force which which is in the negative direction, we take the force and subtract it from 2000N and divide by the gravitational constant which should be the correct mass.

3. Two things are wrong/missing. Fearth on Ball in the second diagram should be Fball on Chris . FnetX, we do not know whether or not there are any unbalanced forces in the X direction that may come into effect.
December 17, 2009
20:10
Journal 12/18
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1. The two forces are drawn to show the forces on the ball and the forces on Chris. Two different objects of reference. Yes, two force diagrams are needed to determine the answer of the question, which is solving for FnetY.

2.Yes, because when finding the FnetY Force - 2000 divided by the gravitational constant that should be equal to the mass.

3. FnetX is non-existent in the force diagrams, which should be there. In the second force diagram, it should be Force of the Ball on Chris rather than Force of Earth on Ball.
December 16, 2009
20:08
Homework 12/17
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Choice C:
By exerting a force that isn't perfectly horizontal or vertical, the object has two more forces that need to be found. The forces added would be Fp on obj. x and Fp on obj. y. These two forces added together should be the original force that was exerted on the object, this can be found by what we learned in lesson 16.
December 10, 2009
22:18
Journal 12/11
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1)To represent a cart with the hand acting upon it, the bob in motion, the bob at rest, and the cart in motion
2) The solutions turned out to be the same.
3) The arrow's length changes because of what is stated in Newton's Third Law.
4)We are able to know the force is not zero when it is moving because there is a force of string on the cart.
December 05, 2009
15:23
Homework 12/7
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a) When the Earth exerts a force on the book, the book exerts a force on __________
b) When a table exerts a force on the book, the book exerts a force on _________
c) When a tennis racket exerts a force on the ball, the ball exerts a force on_________
d) When car tires push back on the Earth’s surface, the Earth’s surface _________

a) The earth
b) The table
c) The tennis racket
d) exerts a force on the tires.
December 03, 2009
19:17
Journal 12/4
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1] A(m) = Fnet
2] In agreement, the acceleration of both objects are the same; the mass does not affect the velocity of the object.
3] In disagreement, the bricks should fall at the same rate and no matter how many bricks there are, the force of the earth on the object is still the same no matter what object.
December 01, 2009
18:43
Homework 12/1
» ‎ Nel's Physics Journal

b) You pull a 20-kg sled, exerting an unbalanced, horizontal force of 30 N on it for 10
seconds. (1) What is the acceleration of the sled? (2) What is the speed of the sled after 3
seconds? (3) What force do you need to exert on the sled if you wish to keep it going at
that constant velocity?

Y+
| /
| - | 30 N +
| 20kgO---->
| |
| /
|_____________X +

Acceleration = Force
------
Mass

Acceleration= 30N
-----
20kg

Acceleration = 1.5m/s

Speed of sled after 3 seconds is 4.5 m/s assuming pulling the sled started from a 0 velocity

An opposing force at the same rate of acceleration is needed to keep the sled moving at a constant velocity
November 19, 2009
20:31
Journal 11/20
» ‎ Nel's Physics Journal

1. Why is the object of interest drawn as a dot?

The object of interest is drawn as the dot because the object is what is being acted upon.

2. How do you know how long to draw the arrows attached to the dot?

You know how long to draw the arrows attached to the dot by how much force is being pushed upon the crate. The two forces, the force of the floor on the earth and floor on the crate should be equal.

3. Why is there no arrow labelled F(man on crate) in the force diagram in the video?

The man is not creating an exerting force on the crate, the earth is.

4. In general, what can you tell about the object of interest by examining a complete force diagram?

The crate is at equilibrium at a vertical standpoint however, horizontally the crate is being forced in a direction.

5. In general, what can you NOT tell about the object of interest by examining a complete force diagram?

Whether the object of interest's velocity when moving will accelerate or not.

6. What do you know (and what do you NOT know) about the MOTION of the object shown in the force diagram below?

What is known about the motion of object is that it is not moving vertically because there are two forces that are equal. What is also known is about the motion of this object is that it is moving in a direction (right) because there is only one force acting upon it. What is not known about the motion of the object is the velocity of it's motion.
November 01, 2009
17:14
Journal 10/29
» ‎ Nel's Physics Journal

In agreement with Jenny. The green car overall has the highest ending velocity, but although the pink and blue car had greater acceleration rates, the ending velocity was nowhere near the same.

Pat thinks the cars stop at 17 seconds because the last car no longer accelerates after 17 seconds. He is not aware that although the cars are no longer accelerating, it does not necessarily mean that the cars are not moving. Velocity still exists however there is no change.

The pink car has the greatest change in position during the time interval t=3 and t=5. The reason for this is because the pink car's velocity is 30 m/s while the others are only 12 m/s (Green) and 15 m/s (Blue)
October 22, 2009
22:37
Journal 10/22
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A car moves straight in one direction at a velocity of 10 m/s for 5 seconds. It then stops and stays still for 10 seconds. Finally it travels in the opposite direction at 7 m/s for 10 seconds. It then stops completely.

Richard's Position vs. Time graph doesn't work because when the car travels in the opposite direction, the position should be increasing, not decreasing. The Velocity vs. Time graph does not match because the Velocity is not a negative trend.

Eva's Postition vs. Time graph matches the description perfectly. Eva's Velocity vs. Time graph also matches the description perfectly.

Dorothy's Position vs. Time graph matches the description perfectly however it is preferable to have started from an even number on the graph. Dorothy's Velocity vs. Time graph does not match because according to her graph the velocity is -10 m/s which does not match the positive trend.

Both of Eva's graphs are superior to the rest of the graphs. The graphs match the description of the movement of the car in every aspect where as the other graphs do not completely match the description, with the exception of Dorothy's position vs. time graph.
October 15, 2009
20:10
Journal 10/16
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WEST:: ::EAST
TRAIN
-------------------------------------------------------
Meagan+Beccy [Andrew] _______________________________________

Train traveling eastwards.

LEGEND:
[] Stationary position

-The object of reference is the Train.
-Coordinate positions East + West.
-The train is moving faster east than Ryan is walking west.
-Because the train is moving faster east than Ryan's path of walking west, Ryan is still moving in an easterly direction.
-Meagan's first statement that Ryan is walking west because he is about to bump into Andrew is true, however her second statement is not completely true.
-Beccy's statement is not true because the train is the object of reference and Ryan is inside of the object of reference. Ryan is still moving westward, however the train is still dragging him eastwards. Ryan is just moving inside of the object of reference.
October 08, 2009
22:24
Journal 10/9
» ‎ Nel's Physics Journal

1. What is shown in the video is a couple of people who were not able to see their own reflections in the mirror however a woman standing directly beside them is able to. Whats interesting is that when those that are not able to see their reflection move in the same position where the lady who is able to see her reflection, they are still incapable of see their reflection.

2. How this video might have been created is that a glass may exist in a frame however the mirror is actually much further away than glass and very slightly convex and the image gets produced into an opaque object that doesn't reflect light. (or maybe they're just vampires.)

3. This proves that the image that is supposed to produced below the main axis can't be seen.
October 04, 2009
$Permalink for 'Refraction Lab 10/1 repost'$ 21:52
Refraction Lab 10/1 repost
» ‎ Nel's Physics Journal

A) The idea I am testing is that If Snell's Law is true, if I point the laser into the water at a 45 degree angle, the refractive ray should bend closer to the normal based on what Snell's law states.

B) The experiment I am going to conduct is that I am going to aim the laser into the water at a 45 degree angle from air into container of water.(shown below)

C) My prediction is that the refractive ray should bend into the water towards the normal based on what Snell's law states. (shown below)

D) When actually conducting the experiment, the light does not bend in the water, but the light rays spread along the plastic perimeter. Snell's Law is not necessarily dis proven however, it becomes not true once it reaches a certain incident angle, which is 42 degrees.

Also (theta2)=sin-1(1.33sin45)
______
1.0

Does not work when plugged into a calculator; this is more proof that Snell's law does not work at this point.

E) This lab was conducted to teach us that although some things may seem true and accurate on paper, when an experiment is physically conducted, a law may not work the way that it is stated.
21:51
Journal 9/25 repost
» ‎ Nel's Physics Journal

The incident beam, incident beam's normal, and the reflective beam along with the normal are drawn correctly. The second reflective beam is also drawn correctly. The only thing not drawn correctly is the normal, which needs to be adjusted

The incident beam, the incident beam's normal, and the reflective beam along with it's normal is drawn correctly. The second reflective beam is not drawn correctly. What needs to be changed is the angle of the second reflective beam.

The incident beam, incident beam's normal, and reflective beam are drawn correctly. The normal and second reflective beam are not drawn correctly and need to be adjusted.

-------

In my opinion...

Andrew,

Did the best overall work. I believe this because this diagram shows the most accurate path of the light ray. Drawing the normal incorrectly is a minor flaw in comparison to not correctly judging where the path of the light is.
October 01, 2009
$Permalink for 'Refraction Lab 10/1'$ 21:36
Refraction Lab 10/1
» ‎ Nel's Physics Journal

A) The idea I am testing is that If Snell's Law is true, if I point the laser into the water at a 45 degree angle, the refractive ray should bend closer to the normal based on what Snell's law states.

B) The experiment I am going to conduct is that I am going to aim the laser into the water at a 45 degree angle from air into container of water.(shown below)

C) My prediction is that the refractive ray should bend into the water towards the normal based on what Snell's law states. (shown below)

D) When actually conducting the experiment, the light does not bend in the water, but the light rays spread along the plastic perimeter. Snell's Law is not necessarily dis proven however, it becomes not true once it reaches a certain incident angle, which is 42 degrees.

Also (theta2)=sin-1(1.33sin45)
______
1.0

Does not work when plugged into a calculator; this is more proof that Snell's law does not work at this point.

E) This lab was conducted to teach us that although some things may seem true and accurate on paper, when an experiment is physically conducted, a law may not work the way that it is stated.
September 27, 2009
0:58
Journal 9/25
» ‎ Nel's Physics Journal

The incident beam, incident beam's normal, and the reflective beam along with the normal are drawn correctly. The second reflective beam is also drawn correctly. The only thing not drawn correctly is the normal, which needs to be adjusted

The incident beam, the incident beam's normal, and the reflective beam along with it's normal is drawn correctly. The second reflective beam is not drawn correctly. What needs to be changed is the angle of the second reflective beam.

The incident beam, incident beam's normal, and reflective beam are drawn correctly. The normal and second reflective beam are not drawn correctly and need to be adjusted.

-------

In my opinion...

Andrew,

Did the best overall work. I believe this because this diagram shows the most accurate path of the light ray. Drawing the normal incorrectly is a minor flaw in comparison to not correctly judging where the path of the light is.
September 24, 2009
16:21
Journal 9/25
» ‎ Nel's Physics Journal

The incident beam, incident beam's normal, and the reflective beam along with the normal are drawn correctly. The second reflective beam is also drawn correctly. The only thing not drawn correctly is the normal, which needs to be adjusted

The incident beam, the incident beam's normal, and the reflective beam along with it's normal is drawn correctly. The second reflective beam is not drawn correctly. What needs to be changed is the angle of the second reflective beam.

The incident beam, incident beam's normal, and reflective beam are drawn correctly. The normal and second reflective beam are not drawn correctly and need to be adjusted.

-------

In my opinion...

Andrew,

Did the best overall work. I believe this because this diagram shows the most accurate path of the light ray. Drawing the normal incorrectly is a minor flaw in comparison to not correctly judging where the path of the light is.
September 22, 2009
0:00
Journal 9/18 Continued.
» ‎ Nel's Physics Journal

How did you disprove the idea that each point on the light bulb emits one light ray? Describe how you used this idea to make a prediction that did not come true.

The idea that each point on the light bulb emits only one light ray was dis proven when a layer of tin-foil with a pin hole at the top covered the light bulb in the dark room. When the light bulb was turned on, various amount of light beams were shooting out in different straight directions from the pin hole. This experiment proved that the light bulb emitted more than one light ray.
September 17, 2009
15:08
Journal 9/18
» ‎ Nel's Physics Journal

What did you do in class today? What did you learn, and why do you believe it?

In class today, we did an experiment involving a light-bulb in a dark room. We were then given two models in the packet, one being a model that correctly demonstrates where/how the light reflects to our eyes and the other being an incorrect model.

What I learned was that the second model was the correct model and that light spreads off in multiple directions evenly distributed. I believe this because the experiment that had been conducted proves it so.

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