# Terminal Velocity. A body in free-fall

## Terminal Velocity. A body in free-fall

• Submitted By: etanaply
• Date Submitted: 04/29/2013 5:18 PM
• Category: Science
• Words: 843
• Page: 4
• Views: 104

A body in free-fall is effected by three forces: gravity, air resistance, and wind force. As a body falls, there is a constant force of gravity; as a body falls faster, there becomes more air resistance. When the air resistance--determined by thickness or density of the air--equals out with the gravitational force, the body reaches terminal velocity. If there is little to no wind force, a human should reach terminal velocity rather quickly. A quick descent was the expectation for both Felix Baumgartner and Lt. Col. William Rankin, but air resistance and wind force easily create the improbable.
First off, let's examine Baumgartner's situation. Felix Baumgartner is a 43-year-old Austrian, who spent more than 5 years of his life planning a 24-mile jump over the New Mexico desert. Felix's goal was to be the first person to go faster than the speed of sound without propulsion. "Fearless Felix" reached a speed of 1,342.8 kilometers an hour (834.4 mph), breaking the sound barrier. Baumgartner ascended 39,045 meters in a hot air balloon, then jumped. He was in free fall for about 37,000 meters until his parachute opened at 2,516 meters above the ground. His free fall lasted 4 minutes 20 seconds, and his total descent lasted 9 minutes 3 seconds. Felix's feat was posted live on YouTube, drawing more than 8 million simultaneous views. When Baumgartner got up into the Stratosphere, the heater on his visor broke. He risked this, not wanting to delay his jump until June 2013. He already had decent weather to fill the balloon, and there was little wind. If more had happened, his Plan B was to deploy the 'chute after 30 seconds, so he'd be safe. About half of the nine-minute descent, Felix was in free-fall, spinning uncontrollably. "Landing on his feet in the desert, the man known as 'Fearless Felix' lifted his arms in victory to the cheers of jubilant fans and spectators" (Roswell, N.M.).
Now, let's take a look at Lt.-Col. William Rankin's story. Rankin was...