Welcome to Physics class!


Hey, everyone on the Vizzed Board! There's been nearly 100,000 posts on this board, but how many posts involved confusing mathematic equations? Better yet, how many posts on this board EXPLAIN all those confusing equations?

Good luck finding another thread like this on the board! It's time to learn physics everyone! Class is now in session!

L E S S O N 1

INTRO: About Physics; what is it?

Physics is a subject about literally everything existing in the universe; yeah, that's kind of hard to take on at once. That's why we're all going to be a virtual study group here at Vizzed so we can learn in little chunks of information, and to learn in a comfy, no-rush environment.

FAQ
What will 'LESSON 1' cover?
Lesson 1 will be the bare basics of physics. We'll start with Frames of Reference and gravity's calculations. We will also be learning about combining forces, and a little bit about vectors.

Will there be any homework? Blah...
No, there won't be homework. This subject on the board is at a stage where you should WANT to learn something. There are no grades, homework assignments, or projects to hand in.

But I don't want to learn Physics!
Unfortunately, within the next ten to fifteen years (due to advancing scientific studies), Physics will be like basic math for us; we will need to use it very often for many things. Hopefully this fun new approach to Physics will be a good motivator for all of us to learn it more!

LESSON 1 VOCAB
OK, what you'll be wanting to do right now is to open a word processor program and have it in a tab so you can write these notes down for vocabulary.

1) Frame of Reference- A frame of reference is literally a frame of motion to refer to; for example, if you're in a train, and it's going 80 miles per hour, you remain in a still frame of reference but you are ON a frame of reference that is in motion. And, if your train is going 80 MPH north, and a train to your left is going south at 80 MPH, then in your frame of reference, it's really going 160 MPH.*

2) Gravity- Gravity is learned right when you get into school; you fall down, it hurts. You throw a ball up in the air, and it comes down to the ground quickly. In Physics, gravity is represented by a lower-case g in equations. **

3) Scalar- OK, you probably are thinking right now, 'What the hell is a scalar?!'. Well, a Scalar is a variable with a magnitude. This word will be discussed later on.

4) Vector- You've seen "Vector" in Xenosaga, but it's not an evil corporation bent on wiping out your overly-cleavaged robot friends. A vector is a variable that has a magnitude AND a direction, meaning it's moving in a given direction and having a certain amount of speed/force. (i.e, going 25 MPH southwest).***

*Frames of Reference
As defined before, frames of reference can be moving or at rest. Frames of reference will be shown in two examples in this part.

EX 1.

Suppose your friend is driving your car, and you are in the passenger seat. You have a baseball in your hand, and you see someone you hate standing on the sidewalk up north. I dunno, maybe he pantsed you or something . You throw the ball at 65 MPH, and the car is going at 30 MPH. Since the car is going north, and you throw the ball north, the wind being pushed from the front of the car will make resistance for the ball. This means that the force going south (the wind) will combine with the ball going north, making it 35 MPH of force.

EX 2.
Suppose you have the ball, was ready to aim it, but you drove by the person too fast, so you chuck the ball at him (south) while the car's continuing to go at 30 MPH. The ball is at 65MPH speed. The wind being pushed south combines with the ball going south which makes it going at 95 MPH! Damn, that's gonna hurt.

**Gravity

Gravity is represented as g in equations (which will be discussed in the future). On Earth, everything falls at 9.8 meters per second squared (No, this doesn't mean you do 9.8 x 9.8 to get an answer for something falling). It doesn't matter if you're in Narnia or Rhode Island, everything on Earth falls at 9.8m/s².

EX 1. Gravity is, in a sense, a type of vector, because any object falling is technically going in a direction (as in straight into the ground), hence why you shouldn't get smashed drunk and try to jump off a hotel roof into the pool.

EX 2. Gravity is a non-contact force (non-contact forces will be discussed in the next lesson). This means you're not being physically PUSHED down by a solid object, you're just going downward (trippy, right?!). If gravity was a contact force, life would effing suck.

***Scalars and Vectors
Scalars and Vectors are 2 different things (obviously, or they'd be the freaking same, like the last 12 iPODs released last week.)

Example of Scalar: Let's use a treadmill as an example. This is basically a scalar machine! It's rotating at a speed, but not going in an actual direction; it's staying in place. Remember that next time you're running on a treadmill, you're a scalar with legs! . Scalars just have speeds, but aren't going anywhere.

Example of Vector: Screw the treadmill, it's too expensive! You're going to go for a good old fashioned run. When you go outside, you're obviously not going to jog in place, right? Your neighbors would be staring at you like you're some sort of freak . You're gonna try that hill near your house. So, you run southwest at 2 miles an hour (literally. Don't say any higher unless you're as fast as KENYANS [ powerthirst joke ]).

Then, you run down the hill and get tired, so you decide to slow down and run west at 1 mile per hour.
1.0 m/h
------------------------->WEST

And that explains the ENGLISH version of the vector, I didn't wanna explain it in Super-ultra-scientist language because your heads would ASPLODE .

*ring*
Damn, I'm out of time already? Well, see you next time. Remember to study this stuff. You can also stay after class for a few minutes and discuss this, so feel free to post in here whenever you want, this was meant to be a social study group!

*sits in a chair and starts to draw*

Anyways, tanks for the non-head-asplosion-language

I'll probably be posting lesson 2 soon, maybe when a little more activity comes to this thread; I don't want people to fall behind before I move on to the next lesson

I could technically argue that your explanation os Scalar is wrong. Speed = distance/time therefore you are not moving anywhere on a treadmill so you don't really have speed.

However, you didn't say the difference between speed and velocity which should probably be here. Speed is directionless, while velocity has a direction.

So I'm thinking a better example or a Scalar would be something like you went running on the sidewalk, while a Vector would be you ran South on the sidewalk. I could be wrong though, as I don't recall hearing about Scalars but physics class was 5 years ago.

Yeah, the scalar definition has been changed like 20 times... I think some physicists have been getting a little drunk while they were redefining it... But if you ran on a sidewalk, you'd be going in a direction, unless you run in place on it, which would have people stare at you and pull their children closer to them out of fear...

Originally posted by iBOCK3

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Yeah, the scalar definition has been changed like 20 times... I think some physicists have been getting a little drunk while they were redefining it... But if you ran on a sidewalk, you'd be going in a direction, unless you run in place on it, which would have people stare at you and pull their children closer to them out of fear...

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That's if you state the direction....

But what you mean is that you'd be running in place. Basically you are going a speed on a treadmill, but you're not really going in any direction (that's what the "SPEED" thing on the treadmill is for)

Speed tells you how fast you gota run or you get hurt.
Nah, speed refers to how fast the.. tred.. well.. the mill part is moving in the opposite direction to you.


I've done 1 and a half years of physics.. Im sick of it...

Also, vectors are handy, especialy in the computer science area!

And by that I bet you mean Vector Graphics, right?

A vector in physics is kinda same as a vector in CS.

Vector when represented on a diagram (say 3D diagram), has an i,j and k component. This is the sort of like x,y,z.. well ,it is, we just name them different.

So you could launch your rocket at a direction at (5, 3, 6).
But you could also draw a point.. or a corner of a box at (5, 3, 6).

All 3D graphics use matracies and vectors. 2D graphics use mainly vectors. With a vector being position from 0,0.

Yeah, CS has coordinate plains... Almost forgot 'bout that.

So.... How bout that Lesson 2?




*Tumbleweed*

Lesson 2 will start next Thursday. I'll be writing right from my notes.

This is pretty cool. It's been about nine years since I had a basic physics lesson.

LESSON 2: WAVES

VOCABULARY:

Wave- Rhythmic disturbance that carries energy.

Wave Pulse- Single bump or disturbance.

Continuous Wave- (self-explanatory)

Transverse Wave- Wave that vibrates perpendicular to direction of wave motion.

Longitudinal Wave- A sound wave.

Surface Waves- Properties of both transverse and longitudinal.

Troughs- Low points in a wave.

Wavelength- Wave pattern that repeats itself.

Crest- High point in a wave.

Incident Wave- Waves that strike the boundary.

Reflected Wave- Returning wave.

Principle of Superposition- Sum of displacement by the individual waves.

Interference- Superposition of 2+ waves.

Destructive Interference- Equal but opposite amplitude.

Constructive Interference- Wave displacement in same direction.

Node- Pulses at zero (when a wave's energy fluctuates to the midpoint).

Antinode- Large displacement.

Standing Wave- Wave that appears to be standing still.

Law of Reflection- Angle of incidence is equal to the angle of reflection.

Refraction- Wave boundary between two different media.

Diffraction- Small edge of a barrier.

+++_______NOTES________+++

Waves carry energy, but they don't transfer matter.


Symbols: Lambda = wavelength

Electromagnetic waves are transverse waves.

Formulas:
3x10⁸ m/s
F(force) = 1/T(Period; T means Period)

*Formulas will be explained later.

MINI-QUIZ:

If you have access to a printer or a paint program, save the wave diagram and label the Crest, the Trough, and the Node! The first person to PM me the diagram perfectly labeled wins 100 Viz!

See you next lesson! Remember to memorize the vocab! More lessons will come out each week when more notes have been taken!