1. The problem statement, all variables and given/known data Our teacher assigned us this problem of trying to derive and equation from 4 simpler equations and I just can't seem to get the correct answer so I need some help. a= M1g / (1/2)M2+M1 a= acceleration M1= Mass 1 M2= Mass 2 g= gravity R= radius T= tension I= moment of inertia [tex]\alpha[/tex]= angular acceleration 2. Relevant equations These are the four equations at which I am supposed to derive the equation above from a) RT = I[tex]\alpha[/tex] b)M1g-T = M1a c)a = [tex]\alpha[/tex]R d) I = (1/2)M2R2 3. The attempt at a solution I am very close to the answer but no cigar a=[tex]\alpha[/tex]R a= (RT/I)*R a= [ RTR / (1/2)M2R2] a= T / (1/2)M2 a= -(M1a) + M1g / (1/2) M2 a= (M1g) / ((1/2)M2 + M1a As you can see I can get all of it correct except for the "a" on the bottom of the equation is wrong. Does anyone have any idea on what to do here? Thanks in advance.