M, a solid cylinder (M=2.43 kg, R=0.115 m) pivots on a thin, fixed, frictionless bearing. A string wrapped around the cylinder pulls downward with a force F which equals the weight of a 0.670 kg mass, i.e., F = 6.573 N. Calculate the angular acceleration of the cylinder.

If instead of the force F an actual mass m = 0.670 kg is hung from the string, find the angular acceleration of the cylinder.

*********** How far does m travel downward between 0.550 s and 0.750 s after the motion begins?

the problem i am having with is *********** How far does m travel downward between 0.550 s and 0.750 s after the motion begins? *****

this part of questions.

i found first answer: 47.3 rad/s^2

second answer: 30.3 rad/s^2

and for the third one,

i've tried

d=(0.5)(a)(t)^2

at 0.550s

d=(0.5)(a)(t)^2

=(0.5)(30.3)(0.550)^2

= 4.58 m

at 0.750s

d=(0.5)(a)(t)^2

=(0.5)(30.3)(0.750)^2

= 8.52 m

and i subtracted them and got 3.94 m but its wrong

i've tried -3.94 as well but wrong as well

what did i do wrong?