**SAT 2 Physics Discussion Thread Nov 2015**

yes that one M,o.5m ithink? what was the answer?

@guy6127 It has to be somewhere in the middle. Otherwise, the net force will point left or right. So, it’s either between Q and planet X or planet Y. If the point is closer to planet X(the bigger one), then the net force will be directed to the left since the gravitational from planet Y is too small. Therefore it must be between Q and planet Y, the planet on the right.

Too bad i missed that. Thanks for the explanation

What about the one with the loud speakers, motor, etc?

@Defeat I made an educated decision and went with electron is negative or something??? (Because it relies on electricity?)

Forgot the choices

@Anubis13 my thoughts exactly. I too have taught myself on most of the concepts and really understand where you’re coming from. Going through 75 questions by random guessing and without careful analysis (in my opinion) goes against everything physics stands for

@guy6127

Choices were:

Electron was negative
Electromagnetic waves do not require a medium to propogate… <Something along those lines
There were more but I forgot.

@Defeat It should be the fact that opposite charges repel each other. Otherwise, even if electrons are negative, if they don’t repel then there will be no current.

Cant remember what i put, but it was related to working of a motor, electrical to machanical, i think?

@guy6127 the force do is zero between the mass on the right and the point on the extreme right. Gravitational force is an attractive force and each mass is pulling the other to itself. The only point where the magnitude of the gravitational force is strong enough to equal the equal and yet opposite force of the first mass is to the right of the mass itself

I think the curve would be around -15 = 800

@dogeater

Yeah, that’s what I put too.

Also, what about the one with the steam?

I: More temperature = more steam per second
2: Tempature would increase (I know this one was false)
3: Steam’s temperature would increase

Also the PV diagram one? It was like which one had constant temperature/pressure, etc.

@Defeat I think it was more power equals more steam released per second. There was no I and III so I just went with I only. The pressure is constant at A, and temperature was constant at B.

b had constant volume, no work as it was parallel to volume

the other was c i suppose

Dont remember the options correctly, there was a very similar PV diagram in PR

@Defeat I don’t remember the exact questions, but I know no work was done on the gas on the sectional that was vertical and temperature was constant on the curve.

Exactly^

What about the standing waves question. whats the frequency it lenght becomes 3/4

What did people put for the first graph? I think i had aa bb or something like that. Skipped 7 guessed half and hoping for an 800