Final answer:
The angular velocity of bar BC exists and is counterclockwise, while angular acceleration exists if the rotation speed is changing. Both may be present simultaneously; they can't be absent unless the bar is stationary.
Step-by-step explanation:
At the instant shown, we would need to determine the angular velocity and angular acceleration of bar BC. Angular velocity, often represented with the symbol w, describes how fast an object rotates or revolves relative to another point, in this case, the axis of rotation. Counterclockwise motion is considered positive for angular measurements. If bar AB rotates counterclockwise with constant angular velocity and block B slides in a circular slot in the curved bar BC, then:
- (a) Angular velocity of bar BC exists and is counterclockwise.
- (b) Angular acceleration of bar BC exists if the rotation rate is changing; it's positive if the speed is increasing.
- (c) Both angular velocity and angular acceleration may be present concurrently.
- (d) It is not possible to have neither unless the bar is stationary, which is not the case here.
If we were provided with a specific scenario, such as gears interacting or an object with changing angular speed, we could provide more precise calculations for both angular velocity and acceleration.