A certain string can withstand a maximum tension of 30 Newton without breaking. A kid ties a 250 gram stone to one end of the string. While holding the other end the kid whirls the stone in a circle of radius 75 centimeter and slowly increases speed until the string breaks.
a. If the circle is horizontal, find the speed of the stone when the string breaks?
b. If the circle is vertical, find the speed of the stone when the stone breaks?