Reviewing Main Ideas 1. A 6.0 kg object undergoes an acceleration of magnitude 2.0 m/s?. a. What is the magnitude of the net force acting on the object? b. If this same force is applied to a 4.0 kg object, what acceleration is produced? 2. A child causes a wagon to accelerate by pulling it with a horizontal force. Newton's third law says that the wagon exerts an equal and opposite force on the child. How can the wagon accelerate? (Hint: Draw a free-body diagram for each object.) 3. Identify the action-reaction pairs in the following situations: a. A person takes a step. b. A snowball hits someone in the back. C. A baseball player catches a ball. d. A gust of wind strikes a window. 4. The forces acting on a sailboat are 390 N north and 180 N east. If the boat (including crew) has a mass of 270 kg, what are the magnitude and direc- tion of the boat's acceleration? Critical Thinking 5. A small sports car collides head-on with a massive truck. Use propor- tional reasoning and Newton's second law to predict which vehicle experiences the greater impact force, and which vehicle experiences the greater acceleration. Use equations to express your reasoning