# Relative angular velocity of one point with respect to another on a solid rigid body [closed]

What is relative angular velocity of A wrt B and that of A wrt C in the figure given below?

Description:

• A, B and C lie on a solid cylinder(rigid body) rotating with a constant angular velocity $$\vec{\omega}$$ about z axis
• A and C lie on the plane perpendicular to $$\vec{\omega}$$
• B lies directly below A with the same distance from the axis as A i.e. they lie in the line parallel to axis of rotation(z axis)

What I think are correct answers:

a) Relative angular velocity of A wrt C is $$\vec{\omega}$$ only (even direction is same as the original $$\vec{\omega}$$). This is proved in the answer of this question:Relative angular velocity of point with respect to another point

b) Relative angular velocity of A wrt B is zero because relative velocity of A wrt to B is zero.

What would be the interpretation of non-zero angular velocity of A with respect to C and that of zero angular velocity of A wrt B? If i sit on C and observe A do i see A moving wrt C, but if i sit on B and observe A will i see A still? If i see A moving do i need to move my head also to continually see A?

• Hint: All points on the same rigid body share the same angular velocity. Commented Sep 2, 2020 at 13:04
• See edited ques. and then why A wrt B will have zero angular velocity? but non zero wrt C Commented Sep 2, 2020 at 13:17
• It's not a homework ques. could you please elaborate on the interpretation part? Commented Sep 2, 2020 at 13:18