Given, mass of bock A,mA=10‌kg Mass of slab B,mB=30‌kg Coefficient of static (µs) and kinetic friction, (µk)=0.6 and 0.4 Applied force, F=100N Acceleration due to gravity, g=10ms−2 According to given figure, NB is normal reaction on slab, B=40g NA is normal reaction on block, A=10g
Static friction force (fs)=µsNA=
6
10
×100=60N Kinetic friction force (fk)=µkNA=
4
10
×100=40N ∵F>fs ∴ There will be relative motion and force on slab B,FAB=ft=40N Acceleration of slab, B=frac‌40‌30=1.33ms−2=1.31ms−2