EPT
[H] Physics, at it again..
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clazziquai
6685 Posts
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Purind
Canada3562 Posts
Last one, I would split each path into components, so for example First path - x1 = -180, y1 = 0 Second path - x2 = 290cos45, y2 = -290sin45 and so on Then the fourth one, which is unknown would be x4,y4, and when you add up all the x's, it sums to 0 and if you add all the y's it sums to 0. It tells you to use a scaled drawing, so I guess you can draw the exact instructions First question, I dunno, maybe they want radians or something | ||
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Kwidowmaker
Canada978 Posts
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Hippopotamus
1914 Posts
2nd one... well you know you can express a vector function as <x(t),y(t)>. It is also a widely known fact that velocity is the derivative of position and that acceleration is the derivative of velocity. 3rd one is just a vector addition problem. vector A + vector B + vector C - Vector D = <0,0>. So just deal with the components, you'll instantly have both answers. | ||
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Luddite
United States2315 Posts
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Hippopotamus
1914 Posts
On September 25 2008 08:57 Luddite wrote: Yeah do what Purind says for the 2nd and 3rd questions. For the first one about the angle, what you did seems right, except I don't see why you need to add 180? Also, make sure you're using the original numbers instead of the rounded off numbers that were your answers to the first part of the problem- that can throw it off just enough to make the software reject your answer. It's best if you have a graphing calculator where you can do all the calculations in one big line on your calculator. --------------> | | | | | | V | ||
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clazziquai
6685 Posts
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Luddite
United States2315 Posts
It would have been right if he hadn't added 180. Or if he had added 360. | ||
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clazziquai
6685 Posts
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Luddite
United States2315 Posts
I think it should be -42.273689 degrees (google calculator FTW). | ||
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capek
United States585 Posts
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CapO
United States1615 Posts
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clazziquai
6685 Posts
That's how one of my answers were 180-42.27 ~= 137. I guess I shouldn't have done that..? | ||
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clazziquai
6685 Posts
On September 25 2008 09:12 CapO wrote: go to the goddamn learning centers. ima report this to the rutgers academic department. NOOOOOOOOOO형!!!!!!!! | ||
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Luddite
United States2315 Posts
On September 25 2008 09:12 clazziquai wrote: I did get -42.27. That's how one of my answers were 180-42.27 ~= 137. I guess I shouldn't have done that..? Actually reading the question again it says "measured counterclockwise" so I guess that means, from the vector UP to the x axis, which would be positive 42.27. That's really annoying that they phrase it in such a deceptive way. I don't know what you're doing with 180 -42.27 though lol. Don't do that. | ||
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clazziquai
6685 Posts
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clazziquai
6685 Posts
On September 25 2008 08:42 Purind wrote: First path - x1 = -180, y1 = 0 Second path - x2 = 290cos45, y2 = -290sin45 and so on So would what woul x3 be? I don't understand what to do for these types of problems... Would it be x3 = 280cos(30) and y3= -280sin(30)? | ||
OneOther
United States10774 Posts
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micronesia
United States24797 Posts
On September 25 2008 12:24 OneOther wrote: Is this AP physics or something? I honestly haven't even read the thread, but just a glance at that picture tells me that it's college or equivalent (not AP) because it's a web submission of answers. High schools rarely do anything like that, and colleges frequently do. | ||
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clazziquai
6685 Posts
guys the last picture I have ONE attempt remaining WOW wtf...I really need help now. I put 210 for Part A but it's wrong... ---------------------------------------- And one more question. http://img255.imageshack.us/my.php?image=physzl2.jpg I'm having trouble with all four of these. Given: Vx= 2.7 m/s Vy= -1.8 m/s t= 10.9 From t1=10.9s to t2=24.0s, the average acceleration magnitude = 0.54m/s^2, at 36 degrees measured from the +x axis and +y axis... I basically got the acceleration for x and y then got their values. Ax= 0.44 Ay=0.32 Then I got the A sub v-x which equals delta Vx over delta time so Vx=2.7m/s+(0.44m/s^2)(10)=7.1 m/s and same for y Vy= -1.8 m/s + (0.32m/s^2)(10)=1.4 I honestly don't know what I'm doing right now..it's due in like 12 hours argh. | ||
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