+- Southperry.net (https://www.southperry.net)
+-- Forum: Social (https://www.southperry.net/forumdisplay.php?fid=14)
+--- Forum: Rubik's Cube (https://www.southperry.net/forumdisplay.php?fid=58)
+--- Thread: Need Help with Physcis (/showthread.php?tid=37334)
Need Help with Physcis - Erebus - 2011-02-04
Should be easy, I just need a confirmation on my process and answer before i turn it in.
Spoiler
Have no idea how to do this...
Spoiler
![[Image: figurew.png]](http://img31.imageshack.us/img31/63/figurew.png)
thanks in advance
Need Help with Physcis - Lozmaster - 2011-02-04
Is the * in the first part supposed to represent a dot product/scalar product? Because you can't just multiply two vectors, lol.
If it is, then its just AdotB=A*B*Cos(theta). Solve for theta [theta = arccos(AdotB/(A*B))]
For part 2, you know the vector a, which you can imagine as being along a Hypotenuse of a triangle. Then ax and ay are the other two sides, how would you use trig functions to find the values for them normally?
parts c and d are the same thing with a shifted co-ordinate system. Just imagine (or redraw it!) to have the x axis now along ax' and the y axis along ay'. Find the new theta between a and ax', and then solve like before
Need Help with Physcis - Shidoshi - 2011-02-04
The dot product (a.b)/|b| gives the magnitude of vector a projected on vector b. This is easier to do than changing systems each time.