Answer
(a) The minimum radius is 920 meters.
(b) F = 5400 N
(c) F = 3800 N
Work Step by Step
(a) $v = (840 ~km/h)(\frac{1000 ~m}{1 ~km})(\frac{1 ~h}{3600 ~s}) = 233 ~m/s$
$a = \frac{v^2}{r}$
$r = \frac{v^2}{a} = \frac{(233 ~m/s)^2}{(6.0)(9.80 ~m/s^2)}$
$r = 920 ~m$
The minimum radius is 920 meters.
(b) Let $F_s$ be the force of the seat pushing up on the pilot.
$\sum F = ma$
$F_s - mg = m(6.0g)$
$F_s = (7.0)(mg) = (7.0)(78 ~kg)(9.80 ~m/s^2)$
$F_s = 5400~N$
(c) $\sum F = ma$
$F_s + mg = m(6.0g)$
$F_s = (5.0)(mg) = (5.0)(78 ~kg)(9.80 ~m/s^2)$
$F_s = 3800~N$
