Question

question 2 (1 point)
a rigid object rotates about a fixed axis; what is true about all the points in the object?
a) they all have the same radial acceleration.
b) they all have the same angular acceleration.
c) they all have the same tangential acceleration.
d) they all have the same tangential speed.

Explanation:

For a rigid object rotating about a fixed axis, angular acceleration ($\alpha$) is the same for all points (since $\alpha=\frac{d\omega}{dt}$ and $\omega$ is same for all points in rigid rotation). Radial acceleration $a_r = \omega^2 r$ (depends on $r$), tangential acceleration $a_t=\alpha r$ (depends on $r$), tangential speed $v = \omega r$ (depends on $r$). So only angular acceleration is same for all points.

Answer:

b) They all have the same angular acceleration.