Pilots of high-performance fighter planes can be subjected to large centripetal
ID: 2237884 • Letter: P
Question
Pilots of high-performance fighter planes can be subjected to large centripetal accelerations during high speed turns. Because of the acceleration the pilots are subjected to forces that can be much greater that their body weight, leading to an accumulation of blood in the abdomen and legs. As a result, the brain becomes starved for blood and the pilot can lose consciousness ("black out"). The pilots wear "anti-G suits" to help keep the blood fromdrainingout of the brain. To appreciate the forces that a fighter pilot must endure consider the magnitude FNof the normal force that the pilot's seat exerts on them at the bottom of a dive. The magnitude of the pilot's weight is W. The plane is traveling at 230 m/s on a vertical circle of radius 690 m. Determine the ratio FN/W. For comparison, note that blackout can occur for values of FN/W as small as 2 if the pilot is not wearing an anti-G suit.
Explanation / Answer
at bottom of circle
FN - W = mv^2/r
FN - W = W * v^2/(gr)
FN/W = 1 + v^2/gr = 1+(230^2)/(9.81*690)=8.815