Projectile Equation Help: Finding Velocity for Water Thrown at 60 Degrees

[reisada]

english is not my native language , ill do my best

Homework Statement

someone wants to throw water to a flower that is to the distance of 5 m and at the same level as the place where the water comes from. air resistance doesn't count

what is the velociity of the water so that it hits the flower, if the water is thrown with an angle of 60 degrees from the horizontal?

Homework Equations

The Attempt at a Solution

already put the parametric equations of the movement :
x=xo + voxt
y=yo+voyt-1/2gt^2
but now i can't do anithing else!

and i can't find any way to find the velocity of the water( the inicial one i think)

anione can help fast please? thanks a lot

 

[scottie_000]

Are you able to write down the equations of motion for a projectile in terms of s, u, v and t?
These are the standard equations one uses to solve such problems
If you can do this, then you need to be able to split the motion into horizontal and vertical components and solve from there.
Let me know how much of that made sense

 

[reisada]

well first of all let me repost :D

the parametric equations are :
x=vo*costeta*t
and
y=vo*sinteta-5t^2

then when vo*costeta*t=5, , when 5 is the reach, we can find the vo
vo=5/0.5t

but now how can i find the time for this equation? am i going well?

 

[reisada]

aha , now ill try to do the position/time which is:

r(t)= vocostetat ex + vosintetat - 5t^2 ey

now if i find the zeros of this function i can get the time right?EDIT : damn this way i still don't know the vo...

 

[reisada]

ok so i restarted the exercise and now i got an answer, can you guys please try to see if this is the correct answer? because this exercise is not from any book with solutions

so this is what i did:
x=vocos60t
y=vosin60t+5t^2

vosin60t+5t^2=0 ( when it is vertically at the same spot as the flower)
t=0 and t= 0,173vo

then

x=vocos60*t
0,5vo*0,173vo = 5 (when x is 5, i calculated the vo)
vo = 7,6 m/s



what was your answer please answer this is really making my mind go crazy :D thanks in advance