## College Physics (4th Edition)

(a) If the net force has a magnitude of 7.0 N, then the two forces must be acting in the same direction. In this case, the net force is 3.0 N + 4.0 N which is 7.0 N (b) If the net force has a magnitude of 5.0 N, then the two forces must be acting in perpendicular directions. In this case, the net force is $\sqrt{(3.0 N)^2 + (4.0 N)^2}$ which is 5.0 N (c) The smallest magnitude of the net force occurs when the two forces are acting in opposite directions. In this case, the magnitude of the net force is 4.0 N - 3.0 N which is 1.0 N.