(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I am working through Boas' Mathematical Methods in the physical sciences book and I don't understand the triple scalar product and torque example.

k [dot] (r X F) = 0 0 1 = xF_y - yF_x

x y z

F_x F_y F_z

k is on the z axis and points in the positive direction. r points in the positive x y and z direction. F points downward in the z direction and it is positive in the x and y direction.

She says "the x and y components of the force can be seen better if we draw them in the (x,y) plane. The torque about the z-axis produced by F_x and F_y is xF_y - yF_x by the elementary definition of torque."

2. Relevant equations

3. The attempt at a solution

I understand that torque is rFsin theta but I don't understand why it isn't xF_x and yF_y

I don't understand why she is subtracting yF_x from xF_y. They are not negative.

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# Homework Help: Triple Scalar Product and Torque

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