1. The problem statement, all variables and given/known data One end of a string is attached to a mass of 7.5kg which is at rest on a horizontal table, coeffecient of friction being = 1/3. String passes through a small hole in the table and supports at its other end a mass of 2.5kg which is revolving in a horizontal of radius 20cm. Find the number of revolutions made per minute if the mass on the table is on the point of slipping. 3. The attempt at a solution I basically did Fc= 7.5*20* w^2 and then Fc=T+1/3*7.5*9.8 and since T would be equal to 2.5*g i subbed that in to get Fc=2.5*9.8+1/3*7.5*9.8 From there equated the two Fc to get 7.5*20* w^2 = 2.5*9.8+1/3*7.5*9.8 And then i just found w and changed into revolutions per minute. Is this method correct? Oh yeah, hi guys as you can see i'm a first time poster and I assume I'll be using this forum, particularly this section, numerous more times in the near future.