Projectile Project Section 2

                        1.       What was your original construction idea?

2.       What challenges did you face in construction?

3.       Did you stick with your original plan?  Why or why not?

4.       Explain how your device works.

5.       Where and how was this device used in history?

6.       What did you learn by constructing this device?

7.       What principals of physics did you utilize in this device?

8.       Tell about a career where this type of device could be useful.

9.       Could this type of device be useful in getting people to space?  Why or why not

 

 

 

 

 

 

 

 

 

1.VIDEO
       2.The "small" parts of the trebuchet was by far the most challenging to change and adjust. The counterweight, the length of the string, the pouch for the projectile, and the tip of the long arm could change the functionality of the device entirely and they all depend on one another.

3. We stayed with our original plan since it's technically "building" it virtually. It won't be easy putting 80ft of 2x4's back together if we encounter an error when we actually start building it.

4. The long arm holds the string which holds the pouch and projectile. The long arm is then pulled upwards by the 40lb/18kg counterweight on the short arm. With the use of PVC pipes and metal pipes, the friction to pivot the long beam is almost negligible...which is necessary since the goal is to swing the long arm as fast as possible.

5. Trebuchets have been used from the 12th Century to modern times. They have been used for throwing dead, infected bodies to cities, boulders to destroy castles, or pumpkins. 

6. As we built the trebuchet, we learned a couple of things: new tools and how to use them, how dangerous it is to build one, how it gets frustrating when measurements are off, and how fun and satisfying it becomes after building it. Other than the ones previously listed, we learned how to have fun with building it... even though it's not perfect.

7. We used the law of gravitation(how gravity affects our trebuchet).Other than gravity, the law of conservation of [insert Physics topic] is/are also used(Come on... almost all of them affect the trebuchet).

8. If you are a high ranking officer in the military, and destroying historic castles or cities with boulders or dead bodies is still a "thing:" then a trebuchet would be the perfect "historical match" for your job, per se. Other than that... a Physics teacher/professor could use this device as a project for his/her students. 

9. Would this type of device be useful in sending people into space? It depends... Since we just learned about "Escape Velocity," the velocity the trebuchet can fire a projectile must be more than, or equal to approx. 25,053 mph: a velocity enough to kill a person, but it will do the job. Other than the trebuchet's lethality, building the trebuchet itself would be hard to accomplish.

To test our trebuchet, we started off doing test fires at random. Seeing if the ball launches too early or too late determines whether if we have to change the angle of the tip of the long arm. The lower the angle of the metal tip relative to the horizontal of the long arm tip, the later the ball is released. With the right angle, maximum distance traveled by the projectile can be achieved. The only problem with this is how to keep the metal tip from changing its angle.

Saftey Concerns

When building a trebuchet, the fear of getting one's face smashed by a 2x4 piece of wood is a good incentive to be careful. Power tools such as the miter saws we used is a hazard to the untrained user. Nail guns become as intimidating as an AK-47 if a person holding it does not know what he/she is doing. Heavy lifting is required, so closed-toed shoes are highly recommended. To remain intact, one must be alert and careful when handling materials and tools. When firing projectiles, the "trigger" must be at least 2 meters away from the trebuchet since many things could go wrong. Warning people in front of the projectile trajectory (unless the goal is to kill or destroy), is highly recommended when firing the trebuchet. The stability of the trebuchet frame must be constant when the trebuchet is firing. To avoid injuries and casualties (assuming the target isn't a city or a castle), one must be on the mindset of "what if [insert worst case scenario] happen(s)?"

Power lab

Procedure:
In this lab, we use electrical meters to calculate our average home's power usage
Question:
1.If you ran up the ramp in half the time of another student of equal weight you did the same work but used twice the power. Explain. This is because p=w/t. The smaller number "t" is the bigger number power is.
2. If the height were reduced by half, the work would be less but the power would be the same
3.Greater power is not necessary, it uses the same amount of power.
4. 66 gallons
5. .134 hp for the light bulb. 150 kW for the engine

Hooke's Law

Procedure:
In this lab we demonstrated the Elastic Limits of Springs and Hooke's Law by adding weights to a string and letting gravity stretch it out. Based on how far it stretched and the actual length of the spring, we were able to calculate the spring constant of the spring.
Questions:
1. Things that may have causes errors in our results was that we couldn't measure the exact changes in spring stretch because sometimes it was a really small change and we didn't have the means of measuring something so small
2. More precision can be added to this apparatus by containing the spring a tube so it can not sway or move when adding weights to it.
3.If you overstretch a spring or rubber band it can either break about and/or it will never return to the shape it once was. It would affect our result because the length of the actual spring without any tension would be longer than normal
4. It looked like a linear graph and the slope represents tension being put on f the spring
5. The minus sign means the force is opposite of the displacement. Meaning if you compress the spring, the spring pushes back at your and vice versa
6. No rubber bands do not obey Hooke's law
7. Most physical factors contribute to the spring constant, i.e. material, weight, mass, length etc.

Transger of Energy lab post 3

Question 1:
Most of the device was pretty even in turns of energy usage but if there was one part that was exceptionally wasteful, it would have to be the gun shooting the tennis ball. Because the gun has a vast amount of energy and power but all it does is push a tennis ball ever so slightly to right.
Question 2:
The transfer that was most efficient was when the tennis ball crashed into the wood blocks and made domino-like effects. The reason I think it was the most efficient is because the tennis ball was relatively slow moving. Yet, it was still able to knock down many big and heavy wood blocks by making a domino effect
Question 3:
I've learned many things about this device, especially how difficult it must have been for the TED talk people to construct something of such magnitude. Every little step has to be perfect and tested many times. Every time you test it you must set it back to it's original state. It's a very tedious and time consuming process, but rewarding when everything works out.

Transfer of Energy Lab Post 2

The project is going well, although albeit a little slower than we imagined. We've abandoned the principle idea of making a cup of coffee. Instead, we have decided that this project will raise a flag of some kind and/or inflate a balloon. A challenging part of the project so far has been getting the switch on the fan cart to turn. We ended up succeeding by looping a piece of string over the knob really tight and then trying a weight to the end that would fall off the table and thus, pull the string and turn the knob.

Transfer of Energy lab post 1

Materials:
Marbles
String
Yarn
Electric car
Pendulum launcher gun
Wood blocks
Foam tubing
Baking Soda
Vinegar
Balloons

Most if not all the materials should be in the storage room. Except balloons, Keyur will bring balloons. Constructing a device that will flip the switch on one of the electric cars seems very challenging. And lining up the gun with the object it's meant to hit will be troubling as well since so many factors play into the trajectory of the ball. If it misses, that will be a big problem.

Soda bottle rocket Post 3

Questions
The maximum amount of force that can be created from 200ml of vinegar is roughly 500N. Careers that would involve this sort of experimentation would be military or civilian rocket programs. If military, than a weapons engineer perhaps and if civilian than an aerospace engineer. These engineers would have to use a test like this in order to find out how much force can be created from a given amount of fuel so they can calculate how much fuel they need to put on the rocket. More fuel than necessary, and the rocket will weigh to much. Too little fuel will result in failure to reach destination. Another use of this type of experimentation is a gun manufacturer. While most calibers are already laid out, those that invented them had to find out how much force a given amount of gunpowder would exert on the projectile and find the point where weight gained is not lowering the speed and accuracy even though there is slight force gain. In other words, they had to find out when they start getting diminishing returns in terms of weight to force of the bullet.
1. Newton's third law states that for every action there is an equal and opposite reaction. For example, a rocket launch. Force of rocket engine going down pushes rocket up
2. Recoil is a good example of Newton's Third law because the original action would be gunpowder ignition pushing the projectile out and the reaction is the force backwards or the recoil
3. You don't observe Ping-Pong paddle recoil because the paddle is a lot bigger and has a higher normal force than the Ping-Pong ball plus your holding it so the force travels throughout your body
4. Because F=ma, F1=12*2.5 And if F1=F2, 30=4*a, acceleration of the 4kg object is 7.5 m/s/s

Soda Bottle Rocket Post 2

Observations
Even though the cap exploded away from the rocket, the bottle moved in the opposite direction as well although not nearly as much. This is due to Newton's third law which states that for every action, there is an equal and opposite reaction. In this case, the force of the expanding gas in the bottle caused the projectile to launch and the bottle to move back equally. The projectile went further because it had less mass to it compared to the bottle.

Error Analysis
The bottle rocket fell of the rollers several times thus incorporating friction into our data which was unintentional. The rollers were intended to get rid of the friction variable but the force was just too much for the straws to stay in position. Another possibility for error was how deep the stopper went into the neck of  the bottle after each trial. And finally, since we had to make our own troughs, we had to adjust the experiment to however much sodium hydrogen carbonate can fit inside our trough, thus giving us different measurement

Coefficent of Friction Post 1

Procedure:
1. Find 2 parings to do together with the rest of the class and chose 3 unique ones
1. Find the mass of every material
2. Find newtons of the material by using a spring scale and dragging it across the surface that particular material is paired with
3. Using mass and netwons, I'll plug the data into the formula to find the coefficient of friction for every combination

Error Analysis:
The spring scales are not the most accurate measuring tool simply due to age and their are on a much larger scale which could make accuracy suffer. Also, the whiteboard surface was slightly curved which may have caused results to differ a little.

Rocket Lab Post 1

Hypothesis:
To find the maximum force that can be created with 100mL of vinegar, we will have to determine force by using F=ma

Procedure:
First we will find the mass of the rubber stopper. Then we will measure out 100mL of vinegar and pour it into the 2 liter bottle. Then, using a aluminum foil trough, we will measure out however many grams can fit into it. Then will lay rollers and place the 2 liter on top of them and prepare for the reaction to begin. Meter tape will be laid out and using distance traveled and mass, we will be able to derive maximum force.

Washers/Elevator Lab

Procedure
For the elevator portion, we placed a scale on the elevator floor and measured the difference in scale readings when someone stood on it going up to going down. Using the change in mass and time we calculated acceleration. For the washers lab, we set up a pully system with a weight on one side and a counterweight on the other to measure force. We weighed it a t rest, then at constant velocity and then when it was accelerating and recorded our findings

Questions
1. The reading of the scale was less than the actual weight of the mass when the scale was decelerating and was greater when the scale was accelerating because gravity pushes things down when the object accelerates upwards therefore reading a higher counterforce. When the weight is going down, it is going with gravity and thus experiencing less weight that normal
2. Newton's second law of motion states that the acceleration of a n object is directly proportional to the net force acting on it, or F = ma. So if someone pushes something with more mass, more force is required to get it to move with the same accelerating versus something that weighs less. Like a full shopping cart is harder t push than an empty. And a empty box is easier to push that a full one
3. Because there is no air resistance in space, both the feather and the rock will fall according to the moon's gravity. So they will both hit the surface at the same exact time since gravity is the only force acting on it.

Ballistic Pendelum Lap Post 3

Questions:
1. Conservation of Momentum was proved because the direction of movement before and after the collision was the same. Conservation of energy was proved because the velocity decreased relative to the size and mass of the bob.

2. K(final) - K(initial) / K(Initial) = ((.009)-(.023)) / .009 = 155% loss of energy

3. If the ball bounced off the pendulum with a smaller fractional loss of energy, then the pendulum would have risen to a higher height by however much less the fractional loss of energy was

4. .Ratio is 2.5*m

91:
Of the two methods experimented with in determining the momentum of the projectile, I would have to say the ballistic pendulum method was more accurate. I say this because the projectile in the ballistic pendulum lab was more controlled and there was little room for the energy of the projectile to be lost outside of the controlled environment With the gun and carbon paper lab, the gun moved after every trial due to recoil, thus skewing the results of the data. However in the ballistic pendulum lab, the gun may have moved after every shot, but since the bob is connected to the system, the bob moved with the gun.

Ballistic Pendulum Lab Post 2

Ballistic Pendulum
Observations:
The projectile slowed significantly after the impact and the collision was totally inelastic. Momentum was conserved going in the same direction as the projectile. Initial Velocity before impact is significantly greater than after the collision

Error analysis:
During some of the trials, the gun could of fired the projectile at a slightly different angle thus being off-center with the force and causing different readings to appear. Another potential source of error is that the bob itself was off center creating some trials that had unusable date. For example, sometimes the projectile didn't insert itself into the bob and would just fly off. Another trial would have to be done.

Gun and Carbon Paper:
Observations:
The projectile never hit the same exact spot two times in a row. Each shot was slightly away from the previous one.

Error analysis:
The carbon paper was not off best quality due to age so marking were difficult to see and sometimes totally invisible. Also, the recoil of the gun after each shot could of shifted the position of the whole system by a few microcentimers which could of distorted the angle leading to irregularities when it came down to measureing exact position of impact.

Data:

 

Dune Buggy Lab Post 2

Analysis and Answer to Question:
Because the time it takes for each dune buggy to cross 1 meter varies very slightly and there is no constant acceleration trend that can be seen from the data, I have determined the dune buggies to be traveling at a pretty constant velocity with no acceleration.

Error Analysis:
Because the time is being recorded by humans, there is a profound room for error. This could of been corrected by using motion sensor gates to get more precise readings. Another possibility for room for error is the time at which both buggies are released as well as their angle of movement. And of course, air resistance could of been an although minute, source of error

Dune Buggy Lab Post 1

Procedure:
1. Lay out measuring tape and put markers on every meter
2. Record how long it take for each buggy to travel one meter
3. Do several trials of step 2 to ensure accuracy
4. Using the data, determine if velocity is constant by comparing times.
5. If velocity is not constant, determine rate of acceleration

Observations:
The dune buggies move at a relatively constant speed, although the red dune buggy seemed to be faster than the blue one. (Fresher batteries I presume?)

Ballistic Pendulum Lab Post 1

Title:

Ballistic Pendulum Lab

 

Procedure:

Method 1

1.      Record mass of projectile

2.      Record mass of pendulum

3.      Measure height of pendulum from the tabletop to the center of mass of the system h₁

4.      Do several trials (5) and measure maximum height of pendulum when projectile gets launched into it h₂

5.      Subtract h₁ from h₂ to obtain h

6.      Plug in h as well as the mass of the pendulum bob and the mass of the projectile into the equation to find velocity v=((M+m)/m)sqrt(2gh)

7.      Calculate kinetic energy by using velocity found in step 6. K=1/2(m)v²

8.      Calculate momentum by using the equation P=mv

 

Method 2

1.      Find xe. That is the distance from the projectile to the carbon paper

2.      Find y. That is the height from the gun to the floor

3.      Find d. That is how far in the ball landed on the carbon paper.

4.      Calculate vo. The velocity of the projectile before the collision

5.      Calculate Ko. The kinetic energy before the collision

6.      Calculate Po. The potential energy before the collision

 

Hypothesis:

I think momentum will be conserved because energy will not be lost in any other form. Therefore, the momentum of the projectile should continue when it hits the bob.

Kinetic energy will also be conserved

 

Materials/Equipment:

-Ballistic Pendulum System

-Measuring tape

-Scale

Vector Lab Post 2

Conclusion:
I had to overcome measuring one very large distance going to one end of the school and then measuring just as vast a distance going to the other end of the school just for two classes. Potential sources of error include tape measure not being totally straight when laid out on the ground and the door has varying widths. The most important thing to consider in this lab is units. Make sure you are using the same units always.

Vector Lab Post 1

Procedure:
1. Use tape measure to get distance from origin to class room door going either left or right
2. Use tape measure to get distance y i.e. towards and away from the school front doors
3. Add up all x values and y values and record them under vector notation
4. Use Pythagorean theorem to find hypotenuse which will give you numerical notation

Equipment:
Tape measure

Constants:
"z" coordinate was always either 0m or 4.15m

Surprising Observations:
The school seems a lot bigger when doing this experiment.

HW #1 - Why am I in Physics AP?

Physics is one of the fundamental core subjects of the hard sciences and it paves the way for our understanding of the universe and how we interact within it. That being said, learning more about physics is truly crucial in that it helps you understand how some of the most fundamental aspects of our universe affect us every single second of our lives in a profound way. Physics is one of my favorite sciences since it has to deal with pretty much any and everything we can see and touch as well as pretty much any and everything we can't see or touch. I am planning to major in the medical field so it goes without saying that I will definitely have to take a huge amount of science courses during my college career, and taking physics now will spare me like four hundred  or a thousand dollars if I were to take it at a four year university. While medicine deals more with chemistry and biology, I will have to take some physics as well so I think this class will not only help me bypass introductory physics when I get to college, but also prepare me for harder physics classes down the line.