A CNC milling operation is carried out by moving the tool from the point A to point B in anti-clockwise direction to cut a slot of quarter circle with center at C, as shown. The coordinates of the points A and B are (0,0) and (10,10), respectively. All dimensions are in mm. If the feed rate at point P along x-axis is 6 mm/min, then the feed rate (in mm/min) at point P along y-axis is ______ . (Rounded off to 1 decimal place)