A trаin аnd cаmera are оn оppоsite sides of a circular lake with diameter 5 km (see figure below). As the train travels clockwise around the lake, a camera is focused on the train rotating an angle (scriptsize theta ) radians. When the train reaches the point marked ( scriptsize P ), the distance between the train and camera is 4 km with that distance decreasing at a rate of 2 km per minute. How fast is the angle (scriptsize theta ) changing at this moment? Include units in your answer.