You are looking at a hot air balloon that sinks vertically at aspeed of 4.5 m / s.
You stand a horizontal distance A from the point in the ground where the balloon will land.
You choose how far away you are. For calculations, you can choose a distance between 100 m and700 m from the balloon landing site.
There is a straight line between you and the top of the balloonthat forms an angle ? with the ground. The ground ishorizontal.
Calculate how fast this angle decreases when the balloon is at a200 m above the starting point.
