<p>so my first post stands? cos if u add up the two velocities with their signs it becomes 0. but the question ask about the guy on the spaceship not a third party stationary so why does the equation still hold :) ??</p>
<p>don't we all just love physics lol. i wish einstein was here.</p>
<p>Because the question asks about the guy on the spaceship, we use the relative velocity formula, which gives .882 !!</p>
<p>no, no, don't put signs. If there is moving radar (on police car, assume :) ), let's say 20km/h, and 2 cars, one moving with 120km/h in the same direction as radar, and 2nd in opposite, radar will measure 100km/h for 1st and 140km/h for 2nd, not -140.</p>
<p>i agree :) cause i put between .6c and c :) it has to be correct :)</p>
<p>The equation for relative velocity is :
<a href="http://i35.tinypic.com/16s2sl.jpg%5B/url%5D">http://i35.tinypic.com/16s2sl.jpg</a>
v<em>sp : velocity of the spaceship with respect to the particle
v</em>se: velocity of the spaceship with respect to the Earth
v<em>ep: the velocity of the Earth with respect to the particle.
Yes, the velocity of the particle with respect to the Earth is negative. But it is the velocity of the Earth with respect to the particle that you need to use. And since v</em>pe is negative, v_ep is positive.
Follow the equation as is and you will get .882.</p>
<p>lol...we should get extra points for our effort in defending our answers.</p>
<p>i concede. i do not have much knowledge in this area :) all the best for 800 guys. lol. i think i need it more though.</p>
<p>Waiiit the one with a and b^2...</p>
<p>It did say that a varies directly as b^2... right...?</p>
<p>answer was a vs sqrt of b right?</p>
<p>...Not if it said what I thought it said...</p>
<p>If it varied indirectly wouldnt it be 1/sqrt b? and that wasnt an option</p>
<p>But like... if it varied directly wouldn't it be b^2?</p>
<p>Liiike.</p>
<p>P varies directly as Q.
P = kQ.
To make a linear graph, you'd graph P vs Q.</p>
<p>...Replace Q with b^2.</p>
<p>????</p>
<p>PROFIT!</p>
<p>Yes but wasnt the line supposed to be straight? if it was b^2 it would parabolic</p>
<p>Not if a varies directly as b^2!</p>
<p>it should be obvious to most CC members, but what was the answer for the questions about the object in uniform circular motion, and the string snapping at 270 degrees clockwise? I put it would go straight left.</p>
<p>Tangent to the circle brah. Luckily that's the one thing I learned in my Phys class.</p>
<p>so does that mean straight to the left?</p>
<p>Yes, this.</p>
<p>cool....maybe a 750 isn't a pipe dream. I guessed like 5-6 and skipped 20. 20!</p>
<p>uhm, for the circular motion question, i though you had to add the vectors? There's a centripetal force going towards the center and the tangential force, and so you add them? It was on my sparknotes test...</p>
<p>I know the velocity is always tangent to the circle, but i think they were asking for something else on the test?</p>
<p>does anyone remember this question in detail?</p>
