posted by Sierra .
A stone of mass 0.31 kg is tied to a string of length 0.65 m and is swung in a horizontal circle with speed v. The string has a breaking-point force of 70 N. What is the largest value v can have without the string breaking?
tension in the string = m*V^2/r
max tension is 70N
so Vmax = sqrt(70*r/m)