suppose you took a 3m long piece of the fishing line discussed ( the line has a test strength of 125lbs) attached a 2.5 kg ball to the end, and spun it overhead. at what speed of the moving ball would the line break?

test strength=mv^2/r

556N=2.5*v^2/3

solve for v

how did I convert lbs force to N?
1 pounds is equal to 4.4482216 newton.
125*4.45=556N