Drawing Free-Body Diagrams (continued) Practice 1. After a skydiver jumps from a plane, the only force initially acting on the diver is Earth's gravitational attraction. After about ten seconds of falling, air resistance on the diver will have increased so that its magnitude on the diver is now equal in magnitude to Earth's gravitational force on the diver. At this time, a diver in a belly-down position will be falling at a constant speed of about 190 km/h. a. Draw a free-body diagram of the skydiver when the diver initially leaves the plane. b. Draw a free-body diagram of the skydiver at the tenth second of the falling. 2. A physics book is at rest on a desk. Gravitational force pulls the book down. The desk exerts an upward force on the book that is equal in magnitude to the gravitational force. Draw a free-body diagram of the book