Answer:
The angular acceleration is zero
Step-by-step explanation:
When an object is in rotational motion, it has a certain angular velocity, which is the rate of displacement of its angular position.
This angular velocity can change or remain constant - this is given by the angular acceleration, which is:
![\alpha =(\Delta \omega)/(\Delta t)](https://img.qammunity.org/2021/formulas/physics/middle-school/qxlulcecsxwdfyzeyjrqv510ex6b4uf8tj.png)
where
is the change in angular velocity
is the time elapsed
Therefore, the angular acceleration is the rate of change of angular velocity.
In this problem, the bicycle rotates at a constant angular velocity of
![\omega=25 rev/min](https://img.qammunity.org/2021/formulas/physics/middle-school/qipz7ku18xb62s9gflxpqn41haet3tho0q.png)
This means that the change in angular velocity is zero:
![\Delta \omega=0](https://img.qammunity.org/2021/formulas/physics/middle-school/nnpmtjuhog5l8phwbwqne9ox4clwmflgh0.png)
And so, that the angular acceleration is zero:
![\alpha=0](https://img.qammunity.org/2021/formulas/physics/middle-school/6z6sy4dlmxvc2n2b2jdx245yml8hx3e0g9.png)