the mass of block A is 80 kg, the mass of block b is 20 kg, and
A is connected to B with the cable and pulley system shown. the
pulleys rotate freely, and the cable and pulleys have negligible
mass. the coefficient of static fricion between A and the
horizontal surface is Ms=0.4, and the coefficient of kinetic
friction is Mk=0.3.
a) initially, block A is being held stationary and the system is
at rest in static equilibrium ....