Physics at MHS Period 5

We took notes on how to make Force Diagrams.

• Define the system with a box
• Treat objects in system as points
• Forces acting on objects are represented as arrows where lenght indicates magnitude, originating from point
• label arrows with agent and object
• draw in grid lines parellel and perpendicular to either surface or direction of motion
• If  the forces are not along gridlines, draw in component x and y parts to existing forces. Make a triangle where the original force is the hypotenuse
• If the object is acceleratin that indicates that the forces acting on the object are unbalanced
• Indicate equal forces with tick marks

Homework: Car lab write up due Mon. Diagnoser website due Mon

~Christa

As some of you may know i was in Hawaii the past two weeks and i got back tuesday and my first day of school was wednesday but its still my turn to blog and it would have been really nice if people had done that from the 17of nov on until vacation started, but what ever. Today we talked about sustainability and then we had a big discussion on what was needed to be changed in our school life and the area around us to make it sustainable to be in. We covered everthing from having a food cart and at our school to starting a new class teaching us what we would need to know to survive in the outdoors or the wild. We then finished up class relating the problems so that they would be relative in physics.

Today we jumped back into the notes that we have been taking over the last couple of days.  We are currently discussing the history of mass, includng its founders, stages, definitions, and future meanings.  We pick up the subject at:

Mass attracts Mass: Newton’s Second Law

• the pull of gravity is proportional to the mass of the two objcects divided by the distance between them squared
• algebraically: Fg [is proportional to] (Gm1m2)/(d^2)  …where G is some unknown constant.

Cavendish Helps Out

• 1880s: Cavendish asks “How much is G?”
• develops a “torsion balance”
• two very massive slugs of metal
• device made the effect of gravity between them more noticeable
• G = 6.67 x 10^-11 N(m^2/kg^2)

The Kilogram

• based on a particular slug of metal  –> in a vault in France, taken out once a year
• its losing mass and NOBODY KNOWS WHY
• if the standard kilogram is losing mass, are we all lsing mass???

Escape Velocity

• 1910’s Goddard launches rockets
• according to Newton, every body, ie. planet, has an escape velocity
• remember the pitcher who pitches so fast that the ball goes into orbit  –>depends on radius of the planet, mass of the Earth, mass of the baseball

Schwarzchild Radius

• planet so massive and compact -> escape velocity was > or = the speed of light (C)
• nothing with mass, not even light, could escape
• Rs = (2Gmplanet)/(C^2) = mplanet x (1.48 x10^-27)

                                          …BLACK HOLE

note: Spaghettification- the elongating and stretching of an object into a string of atoms as the object is being sucked into a black hole…

Einstein Revolutionizes Mass

special relativity:

• mass canot go faster than the speed of light
• within 1% C, mass increases with speed

general relativity:

• mass bends the fabric of space time
• mass bends light  –> proven by the inexplicable appearance of Mercury and strs behid sun during an eclipse

 E=mc^2

• mass and energy are the same thing (mass is crystallized energy)
• nuclear energy/nuclear weapons

Matter and Anti-matter

• normal matter [protons (+), neutrons (neutral), electrons (-)]
• anti-matter [anti-protons (-), anti-neutrons (neutral), positrons (+)]
• made of different quarks
• different characteristics of quarks (spin, charm, strange, color (red, green, blue), top/bottom)
• three quarks required to have “mass” in a classical sense

Dark Matter

• galactic motion was a mystery
• missing mass
• non-visible
• non-luminous matter that doesn’t interact with light
• no electric or magnetic interaction
• something that has no interation with aything…except gravity.

 also…no current homework.

-ellen

*Taken by Brooke

In today’s class, we were given more free time to use as we decided, mainly for working on our launchers and Giant Slingshot lab (the Jello Wars lab). Some groups went outside to finish testing their ranges, while other groups were still building and putting the last touches on their launchers.

We also had the option of working on any of the homework that is due this week.

Homework:

• Unit IV Worksheet 3 – due Friday
• Giant Slingshot Lab (all three parts) – due Friday
• Personalized Hippocratic Oath – due Thursday

~ ERS

today we started by doing a worksheet with v vs. t, x vs. t, and a vs. t graphs. this had us anaylizing one of those graphs and making the subsequent two from that information. we then compared each other’s to make sure that we all had the right answers. after that we did another worksheet that had us making a motion map of a car’s negative acceleration, then making a, a vs. t graph of this, then answering some other questions. after that we took some notes and learned how to use the quadratic equation with our situation of a ball being dropped off a cliff.

Homework: finish up back of graph worksheet, due thursday.

We started the class off with working on the Giant Slingshots (Part 3) worksheet. By doing that worksheet we came up with a new equation that we added to our equation chart. Then we talked about the Jello war, which will be held on Monday, November 3rd. Then we used the rest of class to split off into our teams and do any last work we had left for the jello war.

Homework:

Unit VI Worksheet 3~ Due Halloween

The oath~ Due Thursday, October 30th

Slingshoot lab (Parts 1, 2, and 3)~All due Friday, October 31st

~ZV

Today we began work on the Jello wars.  We divided into groups of 4.  Each group picked a launcher and began firing tennis balls from it.  We recorded distance for 3 trials each at 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 degrees.

In class on Friday, We began to talk about Jello Wars. We discussed the setup for the war. We also talked about the importants of projectile motion with our “Jello Shooters”. We used equations that would help us figure out what the trajectory of an object would be. The final thing we talked about was a good  design. It is important to have a good design so that the projectile can go further.

Ryan

Today in class, Ken Jones came in to talk with us about weatherizing. We started with an experiment using ice cubes. The class was split in half and each group had to make to tinfoil boxes and one box made of insulation. One ice cube was put into each. We also put an ice cube on a frisbee as our control. The ice cubes were supposed to have about the same mass. One of the tinfoil boxes was placed on the heating vent in the room. After about half an hour we looked at the ice cubes again and measured the mass. We found that the ice cubes taht were on the vent were completely melted. The control and the one in the other tinfoil box were about the same mass. The ice cube in the insulated box had the highest mass.

We then talked about how when something is hot, the particles are moving faster. We talked about conduction and convection and about insulation. We identified which ways heat was leaving a house, whether it was conduction or convection. We also went over the most important places are that have to be insulated, like attics, chimneys, windows, and doors.

We were showed how to weatherize doors and windows and the different materials that can be used. Then class ended.

Homework is the worksheet that we have due Friday.

~Christa