problem with static friction and force I have been working on this problem all weekend and I just can't get it!! A small object is placed 10cm from the center of a phonograph turntable. It is observed to remain on the table when it rotates at 33 1/3 rev/min but slides off when it rotates at 45 rev/min. Between what limits must the coefficient of static friction between the object and the surface of the turntable lie? Calculate the value of Fc. I believe I found the first part of the question by taking Us=v^2/g*r for each value that it rotates. I think that I need to use the formula Fc=m*v^2/r for the second part of the problem but I have no clue how to find the mass and have looked all through my notes and physics book. Please if you could help me I would greatly appreciate it.