i got a to be 6919.255 N by solving for the resultant force. when i tried to solve for the resultant angel, i used O=tan^-1 (Fy/Fx) .... (-6272.03/-2921.93) and came up with 24.979..then since it have to be in the clockwise direction, i subtracted 180..and got -155. this was incorrect.
In earlier days, horses pulled barges down canals in the manner shown in Fig. 5-47. Suppose the horse pulls on the rope with a force of 7800 N at an angle of θ = 22° to the direction of motion of the barge, which is headed straight along the positive direction of an x axis. The mass of the barge is 9600 kg, and the magnitude of its acceleration is 0.10 m/s2. What are (a) the magnitude and (b) the direction of the force on the barge from the water? (Measure the direction clockwise from the direction of motion, and give your angle to the nearest degree.)