<p>why wasn’t it C for the one with going to the top of the page? It seemed like C and D were going to the top of the page…***?!</p>
<p>what was the answer to the one about which changes during an induced emf?
length of current
strength of B
something else</p>
<p>for the tree-photograph question, was it 0.001?</p>
<p>tree-photo graph was like .0025 or something like that. It’s like proportions.</p>
<p>Length of wire strength of mag field and velocity.</p>
<p>They all affect emf</p>
<p>Emf = -flux/time</p>
<p>I though both D and C were going toward the top of the page. But I tired to imagine wiggling a string and ended up consider many different points in the end I chose C I think.</p>
<p>i also chose C under my own intuition…</p>
<p>anyone certain of their answer?</p>
<p>Which question # was the space suit question? Wish I had the guts to do one pass before answering questions.</p>
<p>What about The block on The frictio
n less surface;it asks what can be determined if The velocity of The block and The height difference is known</p>
<p>Well potential energy of the block I guess. Gah missed so many questions I could have answered U.U.</p>
<p>**** I said all</p>
<p>How about the second last question. Emf of the battery. I chose ‘when the switch is open’. I can’t remember the question though.</p>
<p>^ I chose when r=R :$</p>
<p>Ohh. Do you remember what the question was?</p>
<p>I think emf flows in a circuit when the is no current through the circuit, regardless of the resistance connected. So switch open should be right I think.</p>
<p>if you have mass, velocity and height difference of the block I think you can calculate pe, ke and one other one, I forgot the third option.</p>
<p>"Length of wire strength of mag field and velocity.</p>
<p>They all affect emf"</p>
<p>@Diluvio</p>
<p>emf = -NBAcos(theta)/time</p>
<p>changing the length of the wire has no effect. (you’re probably thinking of F = I<em>length</em>bsin(theta), which doesn’t apply in this case)
changing the field has an effect.
changing the velocity of what? i forgot; the only thing that “time” indicates to us is that the faster we change the flux, the stronger the emf. I don’t think it has to do anything with velocity.
<em>EDIT: wait, if we change the area so fast, such that a rod travels so fast, that would mean the velocity of the rod does affect the emf. *</em>**!!!</p>
<p>Does anyone agree?</p>
<p>I also remember choosing the “switch open”.</p>
<p>I believe there were two questions where they gave us different atoms and asked us about their deflection or something. Does anyone remember? Were they both the same answer? (the biggest mass number?)</p>
<p>What was the one with the energy levels X and Y? I remember doing E = hf, but that didn’t give me any of the answer choices, which had 4*10^-x</p>
<p>This test was not normal; for those who already took the sat physics test, what do you think the curve will be for this one?</p>
<p>induced emf = LVB </p>
<p>L = length of wire in the field
V = velocity of the wire
B = magnetic flux density </p>
<p>they all affect it</p>
<p>@Posterguy
third option was work done by friction, and it could certainly be calculated.</p>
<p>molecular motion except question: weight ?</p>
<p>one answer with PV diagram was: heat removed and temp decreases (heat is directly proportional to temp)</p>
<p>I don’t remember the molecular motion question </p>
<p>For that last question I put heat is added and temperature decrease. Heat in this case = energy = work done by the gas in expanding. </p>
<p>Work done by the gas in physics is taken to be +ve I think (I could be totally wrong). </p>
<p>Temperature is inversely proportional to pressure to temperature definitely decreases.
I am really not sure if heat is removed or added 
You need heat in order to expand right?</p>
<p>Sum of work = change in kinetic energy.
You have the change in kinetic energy, and you have two Ws (mgh and W(friction)). So, it is possible to calculate the work done by friction.</p>
<p>Look at an expansion valve in a refrigerator. The work done is positive. What happens? The heat is removed, and the temp. decreases. (U = Q - W, and my W is positive, my Q is 0 because it’s an adiabatic process, so I’m reducing my internal energy…Since U = (3/2)<em>something</em>T, then my temperature will also decrease).</p>
<p>What was the one with energy level X and Y? Answers were like: 4*10^-x ?</p>
<p>centripetal acceleration doesn’t change, right?</p>
<p>@ccuser001
Are you sure it said work done by friction and not by gravity, because i can’t remember</p>
<p>And it was like E=hf, so i think i got like 4*10^-16</p>
<p>ye it was by friction.</p>
<p>I remember I chose C, but I can’t remember if it was -16 or -17… rm22333, do you remember? please, i really want to know if i got this one wrong too.</p>
<p>@ccuser001, for gravitational force, I chose the element with the biggest mass number. F=GMm/r^2. For the electric force, I chose the element with the biggest atomic number. As atomic number is the number of electrons and Fe=kQq/r^2.
Am I right?</p>