Question

A signal flare is fired upward with initial speed 245 m/s. A stationary balloonist at a height of 1960 m sees the flare pass on the way up. How long after this will the flare pass the balloonist again on the way down?

Answer 1

s=ut+1/2 at^2
1960=245t-4.9t^2
Rearrange to get a quadratic for t: t=10 or 40

Answer 2

The first sighting is at 10 seconds so the second (when it comes back down) is 30 seconds thereafter.

Answer 3

Thanks!!