homework 1/28

1. one of the main concern that critics had of the lunar landing was Buzz Alder's moonwalk dance. They said that if you sped up the dancing, he was just simply running, and that the government had just sped it up at that part to make it look like he was on the moon. However, the scientists took a video of someone dressed in the exact replica of the suit, etc. while they were running. They then took that clip and slowed it down. They concluded that the original video cannot be a fake because Buzz's movements had the bounce of weightlessness and the stunt man's did not. Another issue that conspiracy theorists had was that the flag was fluttering in the video which would have happened only if there was some sort of wind, and there is no wind on the moon. However, when tested, the scientists proved that there didn't need to be wind because the poles were aluminum and every time they were touched, the flag moved. If it had been a conspiracy, there would have been movement every time someone walked past it. There wasn't.

2. I actually like this movie. At first, as they were explaining the consipracy theories I thought i may have believed what they were saying, but after the scientists performed the experiments I was like, why second guess yourself!! Overall though, it was a really cool movie and i really enjoyed it.

Journal 1/22

Assignment: Make a new post on your blog titled "Journal 1/22" and address the following questions:

Part One:

1. I learned that in order to reach the end of a problem and come up with a correct result, you must complete and go through ever step available.

2. I learned that in order to truly understand the momentum conservation, you should draw a bar graph because it shows in a tangible way the conservation of momentum. The bar graph shows how the momentum changes from initial to final.

3. I learned that in order to solve the problem, you need to be able to imagine whats going on, being able to imagine what is going on in the problem so that you can correctly sketch it and draw out the rest of the problem.

Part Two:

1. I know that momentum is found by mass times volume, but what exactly is momentum on a real world scale?

2. Fnet external is the force that is acting on the system? It's the external force on the system right?

Part Three:

When you're learning about momentum it's really important to keep in mind that you always conserve momentum so when you are drawing out your bar graph, both sides have to match completely otherwise it's incorrect.

Homework 1/14

i came up with Katelyn's mallet working the best. If Josh has an axe that he can swing at 12 m/s and it has a mass of 4kg, then it's initial momentum will be 48kg.m.s. If we assume that the zombie is 50 kg moving at a velocity of 1 m/s, then the zombie's momentum will be -50 kg.m.s. When on the bar chart, this leaves a -2 momentum that must be conserved. Seeing as the axe stops when it hits the zombie, then the final velocity of the axe is 0. the zombie slows to a -2 because momentum must be conserved. However, Katelyn's mallet can be swung with an initial momentum of 48, and the final momentum would be -48 because the mallet swings back at the same speed in the opposite direction. Since both josh and katelyn have the same zombie attacking them, the initial momentum of the zombie is again -50. Because momentum must be conserved and there is a -2 momentum that has to remain, the final momentum of the mallet is -48, which means the final momentum of the zombie is 46. Meaning katelyn's mallet works the best because she sent the zombie flying in the opposite direction.

the 3 things i learned today that you don't need to find the final momentum of the zombies to figure out the problems, because as long as you know initial and final of one thing, you know that the final has to equal the conserved momentum; that there's more to science than just straight facts and numbers, it's in the asumptions that real learning occurs, and i found that because of the way we were trying to figure the zombie problems and how up in arms everyone got about not being given numbers and the issues that they had "making" up numbers, however, that's where we really learned. The third thing i learned was that i need to be sure i have an array of weapons around me when zombies attack because i wont know their velocity or their mass so i have to be ready for everything.

Homework 1/12

for situation (1) the cars will continue to move in whichever direction from whence the moving car came. this is because it has the smaller mass and the greater velocity. in situation (2) the pirate ship will move slightly back as the cannon moves forward because the cannon has less mass and a greater delta v and the pirate ship has a greater mass and a smaller delta v.

Homework 1/11

1.b Process: (Time interval): From when Chris leaves his house until he buys a bagel, the money is constant
System: (Chris is the system): He doesn't gain or lose money.

We know this because when you draw out the bar charts, you see that there is no change.

1.c. Process: (Time interval): From when Chris buys lunch to when Charles pays him back.
System: (Chris is the system): Chris starts with 10$ and gains 10$ so his bar chart changes between the two, meaning that the money is not constant.

Homework 1/5

1. The maginitude of the acceleration is equal to speed squared. We know this from the vector and tangent work done in class, the delta v is always inward.

2. Acceleration is equal to speed (v) squared over the radius. We found this based on our drawings from the packet and more delta v and tangent/vector work.

3. since the equation is a= v^2 / r

2= 4^2/r
2=16/r
r= 8