only two horozontal forces act on a 3kg mass. one force is 9.0 N acting due east, and the other is 8.0 N acting 62 degrees north of west. what is the magintude of the body's acceleration. The answer in the book is 2.9 m/s^2. but how can this be? shouldn't the solution be (9 + 8cos(118))/3 = 1.74808 m/s^2 ?