Physics help please a.s.a.p?

A jet pilot takes his aircraft in a vertical loop


(a) If the jet is moving at a speed of 1900 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.


____m


(b) Calculate also the 72 kg pilot's effective weight (the force with which the seat pushes up on him) at the bottom of the circle.


____N


(c) Calculate the pilot's effective weight at the top of the circle. (Assume the same speed.)


____N

Physics help please a.s.a.p?
a) a = v^2/r


6 x 9.8 = (1900/3.6)^2 / r


r = 4737m





b) Fe = mg + mv^2/r


Fe = 72 x 9.8 + 72 x 6 x 9.8


Fe = 4939N (effectively 7g's)





c) Fe = mv^2/r - mg (effectively 5g's)


Fe = 72 x 5 x 9.8 = 3528N