Rock velocity versus distance from camera Rock velocity versus distance from camera Rock velocity (vertical axis in m/s) versus distance from camera (horizontal axis in m). The solid line is the prediction using the software developed for space applications. The dashed lines are the measured velocity in the video, assuming the skydiver was falling at several different velocities. (The skydiver repeated the jump with instrumentation on his body to determine how fast he was falling, but the results showed a lot of variation from one jump to the next.) Where the dashed and solid lines cross show the possible distances of the rock from the camera.