<p>The Earth has a radius of 6,400 kilometers. A
satellite orbits the Earth at a distance of
12,800 kilometers from the center of the
Earth. If the weight of the satellite on Earth is
100 kilonewtons, the gravitational force on
the satellite in orbit is
(A) 11 kilonewtons
(B) 25 kilonewtons
(C) 50 kilonewtons
(D) 100 kilonewtons
(E) 200 kilonewtons</p>
<p>Answer is B...what....how...? :/</p>
<p>Because of the law of universal gravitation!</p>
<p>F = G<em>((M1</em>M2)/r^2)</p>
<p>As a result, the force (and in this question, weight) on an object changes with the inverse square of distance.</p>
<p>shubham, you're given mg.
find m from this (takeg = 10)
Then F = GMm / R^2
where R is distance from center of earth, and M is mass of earth, and m is the mass of the satellite that you just found out.</p>
<p>Quoting wiki :
A fractal is generally "a rough or fragmented geometric shape that can be split into parts, each of which is (at least approximately) a reduced-size copy of the whole,"[1] a property called self-similarity. The term was coined by Benoît Mandelbrot in 1975 and was derived from the Latin fractus meaning "broken" or "fractured."</p>
<p>You'll get many beautiful examples of fractals (visual) if you go through google :)</p>
<p>Re: Superconducting state
Superconductivity is a phenomenon occurring in certain materials generally at very low temperatures characterized by exactly zero electrical resistance and the exclusion of the interior magnetic field.
The electrical resistivity of a metallic conductor decreases gradually as the temperature is lowered. However, in ordinary conductors such as copper and silver, impurities and other defects impose a lower limit. Even near absolute zero a real sample of copper shows a non-zero resistance. The resistance of a superconductor, on the other hand, drops abruptly to zero when the material is cooled below its critical temperature.
All superconductors have exactly zero resistivity to low applied currents when there is no magnetic field present.
The resistance of the sample is given by Ohm's law as R = \frac{V}{I}. If the voltage is zero, this means that the resistance is zero and that the sample is in the superconducting state.
The finer details of why superconductors behave the way they do (Forbidden Energy gap is overcome, eg and 2tg pairing etc) are still being researched.</p>
<p>Someone explain question 23 of bluebook physics, the about pendulum total energy.</p>
<p>hey thanks spidey!</p>
<p>@futurEE
It tells you that the total energy is KE + PE, but at Y, the pendulum has 0 PE so the Total Energy = KE
what is KE? .5mv^2</p>
<p>you have m and v
.5(.05)(3)^2 = .5(.05)(9) = .5(.45) = .23 Joules <--- rounded</p>
<p>there ya go, the answer is C!</p>
<p>I have a question of my own:</p>
<p>lets say you have 2 wires</p>
<p>------>-------
------>-------</p>
<p>both carrying current going the same way, and the distance between them is r.</p>
<p>how do they exert an attractive force on each other? can someone explain the WHOLE concept to me please? (I seem to be having a problem understand this...)</p>
<p>what if they were carrying currents going opposite ways?</p>
<p>thanks!</p>
<p>Using maxwell's right hand thumb rule, if you coil your fingers when y our thumb points in the motion of the current, you get the direction of the electric field...And at the point midway between the two wires, you see that the direction of field is clockwise for one, and anticlockwise for the other, and opposites attract... If the current was flowing in opposite directions it would have repelled.</p>
<p>what about Kelper's Laws?
Are they likely to show up on the test?</p>
<p>last minute question lol</p>
<p>^ I didn't see any Kepler's law last time I took it in June...</p>
<p>HELP! I signed up for SAT II Physics tomarrow, and I am wondering if I should take it... I got 770 last time. I am looking at top ivy league colleges</p>
<p>well judging from your tone, I'd have to say no because you sound like you did not study. 770s not bad for ivy, but then again, it means you missed like 15 questions.</p>
<p>Can anyone else confirm what fireman said about kelper not being on the test? no offense fireman, i just want more conformation.</p>
<p>thanks.</p>
<p>The nice thing about an 800 in physics is that they don't know if you got -12 or -0 :P</p>
<p>Kepler's laws, and yes I do think it's important, at least how the period varies with radius. (forgot which number law that is)</p>
<p>Is this 12 wrong or 12 skipped? If twelve skipped, how many wrong does it convert to?</p>
<p>@tetrisfan</p>
<p>Yes.....sorry for late reply.</p>