\(T - f = m _{ T } a\)
\(f=\mu m_{T} g\)
\(f=0.05 \times 10 \times 10\)
\(f=5 N\)
\(T -5=10 a\)
F.B.D. of block
\(m_{b} g-T=m_{b} a\)
\(2 \times 10-T=2 a\)
\(20- T =2 a\)
Equation (i) \(+\) (ii)
\(15=12 a\)
\(a =\frac{15}{12} \Rightarrow a =1.25 m / s ^{2}\)