**A pilot is flying a small plane at 56.6 m/s in a circular path with a radius of 188.5 m. The centripetal force needed to maintain the plane's circular path motion is 1.89 x** **$10^4$** **N. What is the plane's mass?** ### Answer $F_C = \frac{mv^2}{r}$ $m = \frac{F_c r}{v^2}$ = $\frac{(1.89 x 10^4)(188.5 m)}{(56.6 m)^2}$ $\boxed{m = 1110 kg}$