20. A ball of mass 5.0 kg is tied to the end of a 75-cm length of string. The ball and string are swung in a circle in a vertical plane at constant speed y, which is the minimum speed necessary to keep the string taut at all times. The center of the circle is a distance h = 190 cm above the floor.
Suddenly, the string is released at the instant the ball is at point , located half way from the top to the bottom on the ascending arc. After what span of time does the ball hit the floor?
75 cm
Q
O 0.96
O 0.51
O 0.385
O 0.45 s