A system consists of three masses m₁ ,m₂ and m₃ connected by a string passing over a pulley P. The mass ml hangs freely and m₂ and m₃ are on a rough horizontal table (the coefficient of fiction = $\mathrm{\mu }$ ). The pulley is frictionless and of negligible mass. The downward acceleration of mass m₁ is : (Assume m₁ = m₂ = m)

• A

  $\frac{\mathrm{g}(1-2\mathrm{\mu })}{9}$

• B

  $\frac{2\mathrm{g\mu }}{3}$

• C

  $\frac{\mathrm{g}(1-2\mathrm{\mu })}{3}$

• D

  $\frac{\mathrm{g}(1-2\mathrm{\mu })}{2}$