Homework Help: Projectile motion

1. Jun 14, 2010

mandy9008

1. The problem statement, all variables and given/known data
A fireman 52.0 m away from a burning building directs a stream of water from a ground-level fire hose at an angle of 34.0° above the horizontal. If the speed of the stream as it leaves the hose is 40.0 m/s, at what height will the stream of water strike the building?

2. Relevant equations
Voy=Vo sin θ
t= Voy / g
y= Voy t - 1/2 g t2

3. The attempt at a solution
Voy= 40.0 m/s sin 34.0
Voy= 22.37 m/s

t= 22.37 m/s / 9.8 m/s2
t= 2.28s

y= 22.37 m/s (2.28s) - 1/2 (9.8 m/s2)(2.28s)2
y= 25.53 m
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Jun 14, 2010

dulrich

Your solution method is pretty much correct except for your calculation of the time. The equation you've used is $t = v_{0y}/g$, which is not valid. You can use $t = x/v_x$, however since the horizontal motion has no acceleration. That should do the trick.

3. Jun 14, 2010

mandy9008

22.7 m thanks!