A uniform sphere of radius 5.0cm and 2.0kg mass is rolling along level ground at a speed of 30cm/s. It rolls to rest in a distance of 15m. How large a stopping force acted on it. 15/(2*PI*.005)=47.75rev = 300 rad 15m/0.3m/s=50s => w=6 rad/s. w_avg = (6+0)/2=3rad/s, therefore (alpha)=-.06rad/s/s. Torque T=I*(alpha). I=2/5*M*a^2. Therefore T = -1.2*10^-4 N.m; rxF=T, => F=2.4*10^-3N. Is this correct? Am I on the right track? Thanks.