when force applied on an object is parallel to the displacement of the object then the work done on an object is

θ = x / r

Explanation:

This is an exercise that relates the angular and linear quantities, in the statement they indicate the relationship of the speeds

         v = w r

Linear and rotational speeds are defined

         v = x / t

         w =θ / t

let's substitute in the first equation

       x / t = (θ / t) r

       x = θ r

      θ = x / r

It is important to note that the angles must be measured in radians