,m1=2kg,m2=4kg F1=2N,F2=20N The maximum force of friction that can occur between the two blocks, is fmax=µmg ........(i) Substitute given value in Eq. (i) ∴fmax=
1
2
×2×10=10N and acceleration of the block system, a=
total force
total mass
=
20+(−2)
4+2
=
+18
6
=3m∕s2 The system of block has an acceleration in the left side. The force of friction opposing the motion of the 2kg block in the left side is ma+ force acting in the direction of friction =[(2×3)+2N]=8N Thus, the force of friction acting between the two blocks is 8N.