Question

A ball of mass 3.0 kg is tied to the end of a 50-cm length of string. The ball and string are swung in a circle in a vertical plane at constant speed v, 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. What is the speed of the ball

Answer 1

at the top, centripetal force=mg
mv^2/r=mg

solve for v. keeping a ball the same speed would be very difficult to swing around vertically, because of the effect of gravity.

Answer 2

What then is the radius

Answer 3

50 cm