Using air pressure, the 0.5-kg ball is forced to move through the tube lying in the hori...

Using air pressure, the 0.5-kg ball is forced to move through the tube lying in the horizontal plane and having the shape of a logarithmic spiral. If the tangential force exerted on the ball due to air pressure is 6 N, determine the rate of increase in the ball's speed at the instant Also, what is the angle r from the extended radial coordinate r to the line of action of the 6-N force?