Ok so for the problem i'm mainly having trouble with setting up one of the equations. The solutions manual jumped from: ωiz([(2/5mERE2)/(2/5mERE2) + (2/3mdebrisRE2)]-1) to: ωiz([mE/(mE + (5/3mdebris))]-1) I placed the brackets to clearly separate the fraction from the -1. Anyways i'm having trouble seeing how the math is done to get from the first equation to the second equation, how was it simplified? If anyone is confused on how i wrote the problem please just ask! Thanks!