TERMINAL VELOCITY

Terminal velocity is reached when the force of air resistance pushing up against the falling object ( i.e. skydiver), is equal to the force of gravity pushing the object downward. As the object falls downwards, there exists a drag force that acts to impede the motion. This drag force not only acts in the direction opposite to the motion, but also depends on the square of the speed of the object. When the object begins to fall, the speed is slow and thus its drag force is also small. As the object increases speed, so too does the drag and at some point the speed would increase to a point where the drag force would act to cancel out the force due to gravity. Therefore the body no longer accelerates and the speed remains constant. Drag force is what makes an object slow down as it moves downwards , if weren’t for these air molecules, objects would continue to increase its speed as it got closer to the ground. Different objects have different terminal speeds. The terminal velocity is not only based on the speed of the object, but also on the density of the fluid through which the object moves. Joe Kittinger was one of the first men to reach a terminal velocity, when on August 16th, 1960 he rode a four and a half foot open gondola to 102800 feet. The ascent through which temperatures that fell to ninety-four degrees below zero, took an hour and a half. When he reached his destined height, he stepped out of the gondola and plunged through the stratosphere reaching supersonic speed in the rarified atmosphere. Between 90000 and 70000 feet he experienced great difficulty in breathing , and by 50000 feet his free-fall speed had dropped to two hundred and fifty miles an hour in the denser atmosphere. After he had fallen for four minutes and thirty-seven seconds, Kittinger’s main chute opened, and some eight minutes later he landed at the White Sands Missile Range in New Mexico without any permanent injuries.