It is given that N1 = 2 N and from the figure shown here, we have N1−f = ma
However, m = 2 kg and a = 0.3 m∕s2. Therefore, ma = N1−f (1) Also, we have (f - µN1) R = mR2α However, α = (a/R), therefore, (f - µN1) - mRa (2) From Eqs. (1) and (2), we have N1 (1 - µ) = 2ma 2 (1 - µ) = 4 × 0.3 or µ = 1 - 0.6 However, µ =