Lab+Science+9

This is my Lab Science page. I'll post science homework, projects, and other stuff here :)


 * **Item Name and Link** || **Type** || **Description** ||
 * [[file:graphing motion1.xls]] || scanned pdf || This graphing assignment was given at the very beginning of the year. ||
 * [[file:Julia Writeup2.docx]] || pdf || This is a report of an experiment on the motion of a toy car ||
 * [[file:Photo 6.psd]] ||  || A photograph and sketch of a simple circuit ||
 * [[file:voltage:current.docx]] || docx || Measurements of voltages and currents through a more complex circuit ||
 *  Controlled Experiment ||  || A controlled experiment that I designed myself ||
 *  Design Challenge ||  || A design challenge that I worked on over several weeks ||
 *  Understanding Concepts ||  || Notes, questions, and links related to main concepts from this semester ||


 * **Date** || **Item Name and Link** || **Type** || **Description** ||
 * 10/12/09 || [[file:Julia Writeup2.docx]] || Toy Car Writeup docx file || The writeup to the toy car experiment ||
 * 10/26/09 || [[file:Photo 6.psd]] || Circuit Captioned Photo - .psd || A photo of a circuit, with captions. Sorry, Skitch didn't work so I used Photoshop instead. ||
 * 10/26/09 || [[file:Circut diagram.psd]][[image:Picture_1.png width="228" height="156" link="@happer:this circuit"]] || .psd || Just like the circuit captioned photo, only they're diagrams. The second diagram is more complex than the first, and links to a wiki page with a few more diagrams of the same circuit. ||
 * 10/26/09 || [[file:26hw.pages]] || 10/26/09 hw .pages || homework ||
 * 10/29/09 || [[file:10:28:09hw.docx]] || 10/29/09 hw (ignore the name of the document) docx || homework ||
 * 11/03/09 || [[file:11:5:09 hw.docx]] || 11/5/09 hw || homework ||
 * 11/14/09 || [[file:11:14:09 hw.pages]] || 11/14/09 hw ||
 * 11/16/09 || [[file:11:16:09 hw.pages]] || guess what? ||
 * 11/24/09 || [[file:11:24:09hw.pages]] || 11/24/09 ||  ||   ||   ||   ||

COMING SOON:
 * Controlled Experiment ||  || A controlled experiment that I designed myself ||
 *  Design Challenge ||  || A design challenge that I worked on over several weeks ||
 * Understanding Concepts ||  || Notes, questions, and links related to main concepts from this semester ||

=Physics=

11/11/09 Poky Day Hw The file wouldn't upload... so here's my homework.

//Continue your study of chapter 6. On page 108, do the "review questions" 6-10.//

7) This car would have twice as much potential energy, because potential energy is directly proportional to height. 8) The car with twice as much mass would have twice as much potential energy, because potential energy is directly proportional to weight. 9) It gains 4 joules of potential energy. When it is elevated to a height of 8 meters, it gains 8 joules of potential energy.

10/26/09 Beginning of Second Quarter

We finished our Newton's Laws unit, and now we're beginning the unit on electricity. Check the diagrams and stuff up top ^^ My homework's there too.

Chapter 3 Reflection**
 * 9/3/09

In Chapters 3.1 and 3.2, the textbook discusses acceleration. We learn that acceleration is speed increased by a constant amount each second. Also, we learn that acceleration is always directly proportional to the net force.

Our cars reflect this concept because the force produced by the propeller causes the car to accelerate. From these two lessons, we learn that our cars accelerate at a constant number of units per second squared,and why.

In Chapters 3.3, 3.4,and 3.5, we learn about the relationship between mass, acceleration, and inertia. Objects with greater mass have more inertia, but they will also have less acceleration. Sir Issac Newton was the first to realize this, and his second law states

Acceleration= __net force__ ........................mass We can see this in our toy cars by comparing their mass and relative acceleration. If one big car and one small car have equally powered engines, the bigger car will move longer by itself, but while the engine is still running, the smaller car will move faster.

Friction and free fall acceleration are discussed in Chapter 3.6, 3.7, 3.8. Friction always opposes motion, and the acceleration for any objects in free fall is always 10 m/s^2. This is because of Newton's second law, which states that acceleration equals force divided by mass. The force acting upon an object is always directly proportional to its mass. Therefore, objects always free fall accelerate at the same rate.

Free fall acceleration is not a particularly useful concept when building a motor-powered car. However, friction is always a force to consider. Without friction on the wheels, the cars would not move. The wheels, turning away from the front of the car, are acted upon by the force of friction, which pushes towards the front of the car. The friction moves the car forward.

Chapter 3.9 discusses air drag. Air drag is an opposing force to an object free falling. It gradually reduces the acceleration of an object until it reaches terminal speed. The terminal speed for a large object is higher than the terminal speed for a smaller one.

This means that the information presented in Chapters 3.7 and 3.8 is partly false. Objects do //not// always free fall at the same speed.

Page 36 Questions 14, 15, and 16:**
 * 8/29/09

//14) A different scaffold that weighs 300 N supports two painters, one 250 N and the other 300 N. The reading on the left scale is 400 N. What is the reading on the right scale?//

The reading on the right scale must be 450 N. Because the weight of the scaffold is evenly distributed: 150N <=> 150N Adding the weight of the painters to either side of the scaffold. 400N <=> 450N If the reading of 400N on the left scale is already given, the reading on the right scale must be 450N.

//15) Nellie Newton hangs at rest from the ends of the rope as shown. How does the reading on the scale compare to her weight?//

The reading on the scale equals half her weight.

//16) Harry the painter swings year after year from his bosun's chair His weight is 500 N and the rope, unknown to him, has a breaking point of 300 N.Why doesn't the rope break when he is supported as shown at the left? One day Harry is painting near a flapole, and, for a change, he ties the free end of the rope to the flagpole instead of to his chair as show at the right.Why did Harry end up taking his vacation early?//

When Harry is supported by both ends of a rope, his weight is 250 N on each side. However, when only one side of the rope supports him, his full weight pulls on the rope and breaks it.

Page 35 Questions 4, 6, and 7:**
 * 8/26/09

//4) If a huge bear were chasing you, its enormous mass would be very threatening. But if you ran in a zigzag pattern, the bear's mass would be to your advantage. Why?//

The bear's large mass would not only have more friction with the air and the ground, but inertia and its greater velocity would also keep its mass going in the same direction while you, a smaller mass, woud be able to change directions and switch paths fairly quickly. Assuming the bear followed your path exactly, it would have to slow down at every turn that you made.

//6) Consider a ball at rest in the middle of a toy wagon.When the wagon is pulled forward, the ball rolls against the back of the wagon. Interpret this observation in terms of Newton's first law.//

Newton's first law- the law of intertia- says that every object continues in a state of rest unless acted upon by a force. The inertia of the ball at rest opposed friction (which, without inertia, would have caused the ball to stick to exactly the same spot on the cart) and reduced its force. Therefore, in reality, the ball still moved forward, but with a reduced speed because of the opposing forces.

//7) Why do you lurch forward in a bus that suddenly slows? Why do you lurch backward when it picks up speed? What law applies here?//

Lurching forward in a bus that suddenly slows is a result of inertia. While the bus is slowing, your own inertia keeps you moving forward. Lurching backwards is also a result of intertia. Because inertia would have you keep moving at a uniform speed, you keep going slowly while the bus speeds up. Of course, in both cases, inertia would be countered very quickly by friction with the ground, or the opposing force of a pole, handle, seat, etc. As you can see, Newton's first law of motion applies in both these cases.

Graphing Assignment 1:**
 * 8/24/09

I managed to do this much in 30-40 minutes. It took me a while to figure out Excel... I'm more used to Spreadsheet.