Calculating Changes in Water Speed with Kinetic Energy Equations

[McKeavey]

Homework Statement

It was on a test, not sure if I remember it to the exact word but it went something like..
If the Kinetic Energy of flowing water increases by a factor of 2.25, what is the factor that the speed changes by.
Something like that :S

Homework Equations

The Attempt at a Solution

I said something like..

The square root of 4.5/m

 

[rock.freak667]

Try it like this:

Ek(new)/Ek(old) = 2.25

Ek(new)=0.5mv_new²

Ek(old) = ?

Now just sub it into the equation.

 

[jmb88korean]

Say KE=1 originally. It would become 2.25 if increased by a factor of 2.25. With the Equation KE=.5mv^2, you can isolate the v^2 to get v^2= KE/(.5m). Just replace the values and you would get that answer. 2.25/.5= 4.5 which becomes the square root of 4.5 after you square root velocity