Open-Response Homework 6: Forces Problem 1 (a) Draw a free-body diagram for the skydiver in Problem 4 of Chapter 5. (b) What is the magnitude of the air drag force on the skydiver, after he reaches terminal speed? Problem 2 A person pushes a 10 kg box on the ground with a force of 5 N . Friction between the box and the ground exerts a force on the box in the opposite direction of -1 N . (a) Draw a free body diagram of the box. (b) What is the acceleration of the box? (c) If \( t=0 \) is when the person begins to move the box, how long does it take for the box to be going \( 2 \mathrm{~m} / \mathrm{s} \) ? (d) How far has the box moved after this time has come to pass? Problem 3 A 1-kg book requires a 0.5 N force to start it sliding across a table. Once it begins sliding, it requires a force of 0.25 N to maintain constant velocity. (a) What is the coefficient of static friction between the book and the table? (b) What is the coefficient of kinetic friction between the book and the table? Problem 4 You are seated in a small airplane. The child sitting next to you had been getting a bit loud, so you are letting him sit in your lap so he will be quiet. Your inertia is 60 kg , the child's inertia is 15 kg , and the plane's inertia is \( 10,000 \mathrm{~kg} \). All of a sudden, the plane hits an air pocket and begins to drop at \( |a|=1.5 \mathrm{~m} / \mathrm{s}^{2} \). (Only for a short time, everyone gets out of this okay.) (a) Draw free-body diagrams for the vertical forces on the child, yourself, and the airplane, labelling the forces using the \( F_{b y, o n}^{t y p e} \) notation introduced in the reading and in lab. Make sure the lengths of the force vectors are appropriate for the magnitudes of the forces. Make a notation if you must draw one to a different scale. (b) Identify all the forces that form interaction pairs. (c) Find the magnitudes of the forces. Show your work, or explain briefly how you obtained these magnitudes. (d) When would you feel "heavier," when the plane is accelerating downward, or after it has levelled off again? Briefly explain your answer. Problem 5 Draw a free-body diagram for a \( 70-\mathrm{kg} \) person standing in an elevator carrying a \( 15-\mathrm{kg} \) backpack (do not consider the backpack a part of the person!). (a) if the elevator is not moving, and (b) if the elevator is accelerating downwards at \( 2 \mathrm{~m} / \mathrm{s}^{2} \). In each case, what is the magnitude of the normal force exerted on the person by the floor?