- #1
Markel
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Homework Statement
the question is sample problem 11-3 of 'fundamentals of physics' 7th edition.
Three forces, each of magnitude 2.0N, act on a particle. the particle is in the xz plane at point A given bz position vector r, where r0 3.0M and theta=30°. Force f1 is parallel to the x axis, force f2 is parallel to the z axis, and force f3 is parallel to the y axis. What is the torque, about the origin o, due to each force.
Homework Equations
I'm trying to use t= RxF
the book is using tx= rf1sin(theta)
The Attempt at a Solution
I broke the position vector into components = (2.6, 0 , 1.5) and applied cross product.
(2.6, 0 , 1.5) X (-2,-2,-2)= (3, 2.2, -5.2)
The book gets an answer of (3, 5.2, 6)
I can't for the life of me figure out where I went wrong. I know that the book is right. Because if there is no position in the y direction, so the moment arm is 3 meters. therefore a 2N force should give a torque of 6N. but I have double checked my calculations over and over and can't find my mistake.
Help!