(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

7. A fireman is standing on top of a building 20.0m high. He finds that if he holds the hose so that water issues from it horizontally at 12.0m/s, the water will hit a burning wall of an adjacent building, at a height of 15.0m above the ground. What is the horizontal distance from the fireman to the burning wall? (Already solved)

8. The fireman in Exercise 7 wants the water from the same hose to reach the burning wall at the same level above the ground as he is standing. At what angle must he aim the hose relative to the horizontal?

2. Relevant equations

vf =vo +2at

d=vot + 1/2at^{2}

vf^{2}= vo^{2}+2ad

g =9.8m/s^{2}

I already solved exercise 7 and I found the distance between the buildings is 12.1m.

The correct answer to exercise 8 is 27.7 degrees.

3. The attempt at a solution

First I tried solving exercise 8 as if the horizontal component of the velocity is 12.0, but that didn't work out.

Then I tried solving it with the angled velocity as 12.0m, then finding horizontal and vertical component velocities of that, but I'm having trouble at this point on how to do that. Then after I would use trig to find the angle.

v = d/t

vx = 12.1m/t

t = 12.1m /vx

vx squared + vy squared = 12.0m squared

d=vot + 1/2at^{2}

I tried combining 2 equations but that the answer that I get doesn't work either.

:/

Thanks for any help.

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# Homework Help: Kinematics and Gravity Problem

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