A mass is tied to a 1 m string. The string is attached

Question

to a point on a horizontal frictionless surface and the mass
is set into circular motion. The string will break if tension
becomes larger than 10 N. The maximum kinetic energy
that the mass can achieve before the string breaks is

Answer 1

F = m a = m v^2/r = 10
so
mv^2 = 10 r = 10
Ke = (1/2) mv^2 = 5 Joules