A fire fighter, 50.0 m away from a building ,directs a stream of water from a firehouse at an angle of 30 degrees above the horizontal as in the figure below. If the initial speed of the stream is 40m/s, at what height does the water strike the building?
I. Let's consider the motion by projections: Horizontal: s = v0 cos(30) t Vertical: h = v0 sin(30)t - gt2/2
t = s/v0 cos(30) = 50/40* (√3/2) = 1.44 s h = 40*1/2 * 1.44 - 10*1.442/2 = 18.38 m Answer: 18.4 m