FIGURE 4.4 shows three objects A, B and C are kept in static equilibrium. The mass of B is 2.0 kg. Object A is just about to slide on the table. The coefficient of static friction between A and the horizontal table is 0.30. Calculate the
(a) mass of C = 2.83 kg
(b) mass of A = 6.67 kg

Help me out please, i want to cry.. the answer is already given. But i want to know the working

The air in an automobile tire with a volume of 2.60 ft3 is at 70°f and 21 psig. determine the amount of air that must be added to raise the pressure to the recommended value of 30 psig. assume the atmospheric pressure to be 14.6 psia and the temperature and the volume to remain constant. the gas constant of air is ru = 53.34ft⋅lbflbm⋅r(1 psia144 lbf/ft2) = 0.3704 psia⋅ft3lbm⋅r the amount of air that must be added to raise the pressure is lbm