A rock of mass m is tied to a string of length L and swung in a horizontal circle of rad...

A rock of mass m is tied to a string of length L and swung in a horizontal circle of radius r. The string can withstand a maximum tension before it breaks. (a) What is the maximum speed the rock can have without the string breaking? (b) The speed of the rock is now increased to The original single string is then replaced by N pieces that are all identical to the original string. What is the minimum value of N required so that the strings do not break? Ignore the force of gravity on the rock.