Using the Vernier three axis accelerometer we have preliminary measurements of the initial accelerations of a skydiver (Chris). (Presented as a poster session at the January 2000 annual meeting of the American Association of Physics Teachers, 1/18/00, Kissimee, FL)
Top graph is the total acceleration, bottom graph showes the x, z and z components of acceleration. Chris leaves the plane at around 7 sec (acceleration is initially near 10 m/s2 and suddenly drops towards zero at 7s when he exits the plane). Once in air the z axis is up so the z (and total) acceleration gradually moves towards 10 m/s2 as he reaches terminal velocity at around 20 sec. There are a couple of jags in the graph between 20 and 40 sec - these could possibly be two 'barrel rolls' which Chris did during free fall. Another possibility is he could have hit the accelerometer with his foot. The spike at the end may be the parachute opening or possibly the second barrel roll (we aren't sure).
Get more data! Videotape a jump while collecting data. Replace the CBL with the newer LabPro so that barometric data could be collected simultaneously. Suggestions? (kforinas@ius.edu)
Forward speed on exit - 60 mph No static line Altitude - 10,000 ft (Highest safe dive without oxygen - 15,000 ft) First 1000 ft drop - about 10 sec Subsequent 1000 ft drops - about 5 sec Terminal speed - about 120 mph (Weight does make a difference in falling speed! So does suit material.) Data taken at 0.5 sec intervals Acceleration is in m/s2 Total acceleration is (ax2+ay2+az2)1/2