# Rotating around axis question

Look at picture for more details....

Book says.....
" A body is free to rotate only about the z-axis. Within the body any particle of
mass m can move only in a plane parallel to the xy plane."

What would the xy plane look like? I am assuming by "xy plane" this does not mean x and y axis...?

I added a picture of what I think they are talking about... is this correct??

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cepheid
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Look at picture for more details....

Book says.....
" A body is free to rotate only about the z-axis. Within the body any particle of
mass m can move only in a plane parallel to the xy plane."

What would the xy plane look like? I am assuming by "xy plane" this does not mean x and y axis...?

I added a picture of what I think they are talking about... is this correct??
The xy-plane is the 2D coordinate plane formed by the x- and y-axes. In other words, it is the set of all points for which z = 0.