- #1
Boogeyman
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Homework Statement
A toy rocket consists of a plastic bottle which is partially filled with water. the space above the water contains compressed air.
At one instant during the flight of the rocket, water is of density[tex]\rho[/tex] is forced through the nozzle of radius r at speed v relative to the nozzle. Determine, in terms of [tex]\rho[/tex], r and v:
1. the mass of the water ejected per unit time from the nozzle
2. the rate of change of momentum of the water.
Homework Equations
F=ma
[tex]\rho[/tex]=mass/volume
Area of nozzle through which water passes=[tex]\pi[/tex]r2
The Attempt at a Solution
This is what I did for part 1:
[tex]\rho[/tex]=m/volume
therefore, m=[tex]\rho[/tex] x volume
RE: area through which water exits:[tex]\pi[/tex]r2
therefore, m=([tex]\pi[/tex]r2)([tex]\rho[/tex]) x length
I think the mass per unit time means divide by time?
m/t=[([tex]\pi[/tex]r2)([tex]\rho[/tex]) x length]/t
I do not know how to do part 2..