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Pilots of high-performance fighter planes can be subjected tolarge centripetal a

ID: 1757074 • Letter: P

Question

Pilots of high-performance fighter planes can be subjected tolarge centripetal accelerations during high-speed turns. Because ofthese accelerations, the pilots are subjected to forces that can bemuch greater than their body weight, leading to an accumulation ofblood in the abdomen and legs. As a result, the brain becomesstarved for blood, and the pilot can lose consciousness ("blackout"). The pilots wear "anti-G suits" to help keep the blood fromdraining out of the brain. To appreciate the forces that a fighterpilot must endure, consider the magnitude of the normal force thatthe pilot's seat exerts on him at the bottom of a dive. The planeis traveling at 267 m/s on a vertical circle of radius 760 m.Determine the ratio of the normal force to the magnitude of thepilot's weight. For comparison, note that black-out can occur forratios as small as 2 if the pilot is not wearing an anti-Gsuit.

Explanation / Answer

          Apply Newtons second law for the pilot then                                    W + mv2 / r = FN                                 1+ mv2 / r*W = FN /W                                                    1+ mv2 / r*mg = FN / W                                            FN /W = 1 + v2 / rg                                                        =------------