4. a jet pilot takes his aircraft in a vertical loop. a) if the jet is moving at a speed of 840 km/h at the
lowest point of the loop, determine the minimum radius of the circle so that the centripetal
acceleration at the lowest point does not exceed 6.0 g's. b) calculate the 78 kg pilot's effective
weight (the force with which the seat pushes up on him) at the bottom of the circle, and c) at the top
of the circle (assume the same speed).