Physics
posted by Tammy .
Three vectors, each have a magnitude of 30 units, have their tails at the same oint and are directed 120 degrees from each other. Make a statement concerning the sum of these three vectors.
a) the sum vector is 0
b) the sum vector is greater thatn 30
c) the sum vector is equal to 30
d) the sum vector is less than 30
c) would be the correct answer right? I did v=sqrt(v_x^2 +v_y^2) and got 29.9993 which is quite close to 30.

Do the math in polar:
a@0 + a@120 + a@240
Well, the y components of all three of those add to zero.
Now, the x components is a+ 2a*cos60
which is...