In this question use g=9.81 m s−2g = 9.81 \text{ m s}^{-2}g=9.81 m s−2.
A rescue flare is launched from a point LLL at the edge of a vertical cliff. The initial velocity of the flare is u m s−1u \text{ m s}^{-1}u m s−1 at an angle of 35∘35^\circ35∘ above the horizontal.
The flare reaches its maximum height exactly 1.51.51.5 seconds after launch. It eventually lands in the sea at a point SSS, which is 202020 metres below the level of LLL.
Determine the value of uuu.
Calculate the total time of flight of the flare from launch to landing in the sea.