ok, you are using a centrifuge. the centripetal acceleration of the sample is 5.05E3 times larger than the accelleration due to gravity. how many revolutions/minute is the sample making if it is located at a radius of 4.62 cm from the axis of rotation? i think i use: centripetal accellearion = (v^2)/r so... 5.05E6*9.8m/s = v^2 / 4.62cm v = 47.8167 rev/min. but i get it incorrect.. any hints?