[填空题]
The height, h metres, of a seat on a Ferris wheel aflnlr07d 5-w zys1 oj+hter t minutes is giya da55ekl)c0 ven by y0 5d5)ekalca
$h(t)=-23.5 \cos (0.4 t)+25, \text { for } t \geq 0 \text {. }$
1. Find the initial height of the seat.
Once a passenger's seat is more than 30 m above the ground, there are no trees in view and they can take unobstructed photographs of a nearby city.
2. Given that passengers only complete one rotation on the Ferris wheel, calculate how long they can take unobstructed photographs of the nearby city.
