An aircraft executes a horizontal loop of radius 1.00 km with

solution:

Radius of the loop, $r=1 \mathrm{~km}=1000 \mathrm{~m}$

Speed of the aircraft, $v=900 \mathrm{~km} / \mathrm{h}=900 \times \frac{5}{18}=250 \mathrm{~m} / \mathrm{s}$

Centripetal acceleration, $a_{\mathrm{c}}=\frac{v^{2}}{r}$

$=\frac{(250)^{2}}{1000}=62.5 \mathrm{~m} / \mathrm{s}^{2}$

Acceleration due to gravity, $g=9.8 \mathrm{~m} / \mathrm{s}^{2}$

$\frac{a_{\mathrm{c}}}{\mathrm{g}}=\frac{62.5}{9.8}=6.38$

$a_{\mathrm{c}}=6.38 \mathrm{~g}$