Flying Shogi Posted October 19, 2011 Share Posted October 19, 2011 (edited) I need help with drawing the pictures for the last two problems on the paper. If possible, please check and see if I did everything right for the first 3 problems. I forgot the paper. brb. [spoiler=Paper] Edited October 19, 2011 by UberLughFTW Quote Link to comment Share on other sites More sharing options...
I.M. Gei Posted October 19, 2011 Share Posted October 19, 2011 2nd from bottom: Vx=16m*cos(180-48)+14m*cos(180+31)=23m W Vy=16m*cos(180-48)+14*cos(180+31)=4.7m N root(Vx^2+Vy^2)=23m arctan(Vy/Vx)=11 degrees N of W 23m, 11 degrees N of W Bottom: Vx=82m/s*cos(180-34)+74m/s*cos(68)+77m/s*cos(-18)=33m/s E Vy=82m/s*sin(180-34)+74m/s*sin(68)+77m/s*sin(-18)=91m/s N root(Vx^2+Vy^2)=96m/s arctan(Vy/Vx)=70 degrees N of E 96 m/s, 70 degrees N of E Quote Link to comment Share on other sites More sharing options...
CT075 Posted October 19, 2011 Share Posted October 19, 2011 Top: You could probably use the law of cosines to do the rest, but I'm lazy. Quote Link to comment Share on other sites More sharing options...
Kriemhild Posted October 20, 2011 Share Posted October 20, 2011 (edited) Before I tackle the last two questions, I should point out that you made a mistake in #2. y = 25sine(28 degrees), as you wrote, but my calculator says that it's equal to 11.74, not 16.4 as you wrote. I think you made a mistake when calculating. And even after that, although your x value of 22 m was correct, you were supposed to add it to 12 and perform your angle/displacement calculations using (22+12) = 34 m/s instead. Your angle is supposed to be arctan (12/34) ~ 19 degrees. The resultant is sqrt(122 + 342), which is about 36 m/s. Questions 1 and 3 seem okay, although I generally don't like rounding up values to integers so early in the question, but your final answers seem accurate enough. I'll look at the last two questions now... Edited October 20, 2011 by Kiku-Ichimonji Quote Link to comment Share on other sites More sharing options...
Lord Raven Posted October 20, 2011 Share Posted October 20, 2011 lol oh god... vectors. i love vectors and all but sometimes they just blow me, especially in random numbers problems like this @_@ Quote Link to comment Share on other sites More sharing options...
Kriemhild Posted October 20, 2011 Share Posted October 20, 2011 #4 Total Vertical displacement = 16sine(48 degrees) - 14sine(31 degrees) = 4.68 m Total Horizontal displacement = 16cosine(48 degrees) + 14cosine(31 degrees) = 22.71 m Angle = arctan(4.68/22.71) = 11.6 degrees north of west Total Displacement = sqrt(4.682 + 22.712) = 23.2m Same as Chiki's pet Pikachu... Kam, why on Weyard is your West pointing at the East? #5 Total Vertical velocity (north) = 82sine(34 degrees) + 74cosine(22 degrees) - 77sine(18 degrees) ~ 90.67 m/s Total Horizontal velocity (east) = -82cosine(34 degrees) + 74sine(22 degrees) + 77cosine(18 degrees) ~ 32.97 m/s Angle = arctan(90.67/32.97) = 70.0 degrees North of East Total Velocity = sqrt(90.672 + 32.972) = 96.48 m/s Also matches with Chiki's pet pikachu Quote Link to comment Share on other sites More sharing options...
Kriemhild Posted October 20, 2011 Share Posted October 20, 2011 Oh, right, drawings For #4, just look at Kam's drawing but make it actually go west instead of east. For #5 Quote Link to comment Share on other sites More sharing options...
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