Final answer:
To find the radius where the tangential speed of a disk equals a certain value, we use the formula v = rω, where v is the tangential speed, r is the radius, and ω is the angular velocity. With given angular acceleration, we can derive the angular velocity and solve for r.
Step-by-step explanation:
The question pertains to the tangential speed at a given radius for a disk experiencing angular acceleration. To find the radius where the tangential speed equals a certain value, we can use the formula for tangential speed: v = rω, where v is tangential speed, r is the radius, and ω is the angular velocity. Since angular acceleration (α) is given, and tangential acceleration (at) is at = rα, we can derive the angular velocity at a given time if needed and then solve for r to find the radius at which the tangential speed is equal to the specified value.