A ball of mass 0.4 kg is attached to a string of length 0.8 m. The ball is rotated in a vertical circle such that the speed at the lowest position is 6.0 m s−1.
What is the tension in the string when the ball is at the lowest position?
A. 4.0 N
B. 14 N
C. 18 N
D. 22 N