No, every part of a rotating object does not move with the same speed (instantaneous speed). In a rotating object, different parts are located at different distances from the axis of rotation. As a result, they have different linear speeds and angular velocities.
The linear speed of a point on a rotating object is determined by its distance from the axis of rotation. Points farther from the axis have a greater linear speed than points closer to the axis. This is similar to how the speed of a person on a merry-go-round varies depending on their position. Those seated farther from the center experience a faster linear speed than those closer to the center.
The angular velocity, on the other hand, refers to the rate at which the object rotates around the axis. It is the same for all points on the object since they are all rotating together. However, their linear speeds differ due to their varying distances from the axis.
To summarize, while all points on a rotating object have the same angular velocity, their linear speeds vary depending on their distance from the axis of rotation.