4. An old trick is to swing a pail full of water in a vertical circle. If the person swinging the pail is not to get wet, and the radius of the circle of the swinging pail is 0.900 m. a. Calculate the minimum tangential speed with which she can swing the pail at the top of the swing? b. Assuming the speed in "a" remains constant, calculate the arm force exerted at the i. bottom of the swing