Confused while reading HRK regarding rotational kinematics

[Afo]

Homework Statement

Refer to the two pictures which are from Halliday Resnick Krane Physics 1 about rotational kinematics:

I am confused why the tangential acceleration, $a_T$, is alpha (angular acceleration) times the length of the chimney, L.

My thinking is that it should be the radius of the chimney and not the length of the chimney

Relevant Equations

a_t = \alpha \cdot r

Pic 1:

Pic 2:

 

[Doc Al]

My thinking is that it should be the radius of the chimney and not the length of the chimney

What's the axis of rotation?

 

[Afo]

Assuming that the chimney is not destroyed yet, the axis of rotation is perpendicular to the ground and goes through the center of the chimney. However, this means that it's multiplied by the radius.

However, since the text mentions the length of the chimney, the author's intended axis of rotation would be parallel to the ground. But I don't see anything rotating with respect to that axis

What's the axis of rotation?

 

[Delta2]

No the axis of (this specific rotation shown in the picture) rotation is not the axis of the chimney. Think again please.

 

[Doc Al]

However, since the text mentions the length of the chimney, the author's intended axis of rotation would be parallel to the ground. But I don't see anything rotating with respect to that axis

Hint: The chimney started out vertical. (Presumably. )

 

[PeroK]

Assuming that the chimney is not destroyed yet, the axis of rotation is perpendicular to the ground and goes through the center of the chimney. However, this means that it's multiplied by the radius.

However, since the text mentions the length of the chimney, the author's intended axis of rotation would be parallel to the ground. But I don't see anything rotating with respect to that axis

You mean the chimney should be doing something like this?

 

[Doc Al]

You mean the chimney should be doing something like this?

That would be one amazing chimney!

 

[PeroK]

That would be one amazing chimney!

And one amazing explosives expert!

 

[Afo]

Oh never mind. I got it. I kinda misunderstood what a chimney is. Here's the picture explaining everything: