Answer
$t\approx1.29s$
Work Step by Step
Make a triangle with a height of $35m$ and a base that is parallel to the plane's flight path.. To calculate the distance that the plane will fly, use the side ratio for the tangent of the angle:
$tan\theta=\frac{opposite}{adjacent}$
$tan(4.3^{\circ})=\frac{(35m)}{x}$
$x=\frac{(35m)}{tan(4.3^{\circ})}\approx465.5m$
Convert the plane's speed into meters per second:
$1300km/h\times\frac{1000m}{1km}\times\frac{1h}{3600s}\approx361.1m/s$
Calculate the time for the plane to reach the ground:
$t=\frac{d}{v}=\frac{465.5m}{361.1m/s}\approx1.29s$
