Recitation Activity Force and Free Body Diagrams Name: We think of each force acting on an object as being exerted by another object. The first object exerts a force of equal magnitude and opposite direction on the second object. These two forces together are called an action-reaction pair or Newton's 3rd law force pair. Identify all Newton's 3rd law force pairs on the free-body diagrams for the books. Mark them with an X on the diagrams for the first pair and XX for the second pair, etc. 2. For the following situations: Draw a picture and identify the forces, then Draw a complete free-body diagram for the object, following the steps given above. Draw a vector on your free-body diagram indicating the approximate magnitude and direction of the net force on the object, Fner. If the net force is zero, say so explicitly. a. A heavy crate is being lowered straight down at constant speed by a steel cable. b. A child is pushing a box across the floor at a steadily increasing speed. Let the box be "the system" for analysis. c. A bicycle is speeding up down a hill. Friction is negligible, but air resistance is not