You swing a bucket full of water in a vertical circle at the end of a rope. The mass of the bucket plus the water is 3.5 kg. The center of mass of the bucket plus the water moves in a circle. What is the minimum speed the bucket must be swung so that no water spills out at the top of the circle?
a) √(2gR)
b) √(3gR)
c) (2gR)/3
d) (gR)/2