<p>guessed that)</p>
<p>what is answer for the question with picture about spring and tension or force something like that?</p>
<p>Straight line for F = -kx, parabola for U = 1/2kx^2.</p>
<p>That was awful.</p>
<p>kikuhana: for the particle nature of light I, II, III question you mentioned in post #91, I think it was III only for both of them because for #1, gasses have nothing to do with anything and dispersion patterns proved the wave nature of light, in addition to that choice II’s description of what causes a dispersion pattern wasn’t accurate. And for #2 the photoelectric effect is what releases electrons from metal surfaces. I’m pretty sure.</p>
<p>@kikuhana</p>
<p>for the graphs question i put the answer choice with the sine curves because the restoring force fluctuates with the position. if you had indeed put a linear for the restoring force, then that would mean that the restoring force had no limit, which is not true. At equilibrium the restoring force is zero, and at the x min the restoring force has negative max amplitude (just like a sine graph). but this was just my thought process when i saw the question</p>
<p>Wait, there was a sine graph choice O_O? </p>
<p>Either way, the spring was ideal and followed Hooke’s law, right? I understand what you mean, but if you wanted a graph that accounted for the direction of the force and how it has a max, then wouldn’t you end up with a non-differentiable graph of sharp points o.o?</p>
<p>Edit: You may have been thinking force versus time?</p>
<p>What about the one where it showed multiple velocity verse time graphs and asked : Where is the instantaneous acceleration zero? Which position is the furthest from the initial point? and i think there was one more question on it?</p>
<p>instantaneous velocity, you mean…and the position that it is the farthest is E</p>
<p>I think you mean instantaneous velocity because there was another question related to the graphs that asked when the acceleration was 0.</p>
<p>As for the farthest point it was at point B because the unit was -2 units away from the origin. From Point B to E, the total distance traveled was +2 units. Thus at point E the total distance is 0 units which is not correct.</p>
<p>Ok that is what I got too because since d = vt…i multiplied all of the coordinates of each point and b was the greatest…and yes i meant instantaneous velocity</p>
<p>The three questions on that topic were:</p>
<ol>
<li><p>When is the instantaneous velocity 0. The answer was at B and E, when the graph of velocity vs time equaled zero. </p></li>
<li><p>Between what two points is the acceleration zero? The answer was between C and D, when the line was horizontal. </p></li>
<li><p>At what point was the distance from the location at time t = 0 the greatest. Answer was B. With calculus, it’s essentially finding the max of an accumulating area function. But if you think about it, it goes 2vt units towards the left and then 2vt units to the right, so the max is when v = 0 first, or at B.</p></li>
</ol>
<p>The superconductor one: If there’s no resistance in a superconductor, wouldn’t that mean it would use less energy? (as opposed to making the train go smoother)
The guitar string with thick vs. thin wire: v=sqrt(Tension<em>L/m). So increased mass = less velocity. v=f</em>wavelength, so if v goes down, frequency goes down.
The instantaneous velocity one: Just look at the area under the curve, since the integral of velocity is distance traveled. The most area was from 0 to where it first intersected the x-axis.
Sled #1:Sled away from dock/dude towards dock
Sled #2:: None/None
Capacitance Circuit #1: 8
Capacitance Circuit #2: 6V/3V/3V
Velocity of light changes upon glass: Frequency (different frequencies of light have different indices of refraction, so they have different speeds in glass)
Same effect as in rainbows: Glass prism</p>
<p>What was the one about the teacher making measurements that were off by 25% and 5%? And the one about using a circuit to experimentally confirm Ohm’s law (I think I chose the one where the voltmeter is after the first resistor; 2 of the choices had resistors in series, 2 had in parallel, i think?)</p>
<p>Also…what it the modern view on protons and electrons? I put that they both consist of quarks</p>
<p>And I think it said something on nuclei? the other choices were : they have the same charge, protons cannot decay…I think this was the same question but I’m not positive (no pun intended) lol</p>
<p>According to google, electrons are elementary particles and are not composed of quarks…dang I got that wrong.</p>
<p>The x was 30 percent because by 1.25 * 1.05 (margin of error) you get something like 1.3125? which is about 30 percent</p>
<p>For the Ohm’s law, it was where the voltmeter is parallel to the fixed resistor and the ammeter is in series with all of the resistors. Choice A I believe. The reason is because you need to make a V/I graph. Thus R must be constant and you have to find the relation between current and Voltage. The variable resistor allows you to change the current (independent variable) while the dependent variable is the voltage.</p>
<p>^I put quarks as well. I guess the answer to that one is that protons don’t spontaneously decay. </p>
<p>Also, there was a question about nuclei always being positive? Does anyone remember that question?</p>
<p>Superconductor: Yup! Using a superconductor would use LESS ENERGY. P=IV. Making the train go smoother just requires that a magnetic field does its stuff… However, a SUPERCONDUCTOR uses less power to create such a large magnetic field, since it has such a small resistance. P=I^2*R… I got so confused when people said the answer was that it went smoother…</p>
<p>And regarding the sled, I got the first question (conservation of momentum), however, when the guy stops, it just didn’t make any sense for the sled to stop too… Because there was no friction, the sled would continue to move away from the dock. Sled will only stop from it’s movement if there is a force applied, which there is none…</p>
<p>Can someone explain the guitar strings one? I’m really confused about why wavelength stays the same…</p>
<p>@gravity95</p>
<p>I’m assuming the answer is that they have the same charge. I remember the response didn’t include sign so I’m guessing that they have the same charge 1.6 E-19 C. </p>
<p>Nuclei always being positive? Because they contain protons? I don’t remember that…but it’s been a long day haha</p>
<p>Yeah I remember that one but I don’t remember the question. But I think that was the answer…ugh i think i got it wrong</p>
<p>If the string goes from thin to thick, the mass increases…so since v = √Ft/(m/L), velocity decreases. Therefore, since v = fX(wavelength), if velocity decreases, frequency decreases…think about it…the wavelength of a string cannot change in this case because the length of the string is the same…that is why frequency has to decrease and wavelength stays the same. Atleast thats how I solved it.</p>