Force to hold nozzle with given flow rate and velocity

AI Thread Summary
To determine the force needed to hold a fire hose nozzle stationary while discharging water at 16.0 kg/s and 20 m/s, the relevant calculation involves momentum, not gravity. The correct momentum is calculated as the product of mass flow rate and velocity, which is 16 kg/s multiplied by 20 m/s, resulting in a force of 320 N. The initial attempt mistakenly included gravitational acceleration, which is unnecessary for this problem. Understanding the impulse-momentum relationship is crucial, as impulse equals the change in momentum over time. The key takeaway is that the force required to hold the nozzle stationary is 320 N.
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Homework Statement



A fire hose discharges water at a rate of 16.0 kg/s with a speed of 20 m/s. What magnitude of force is needed to hold the nozzle stationary?

Homework Equations



Impulse= Change in Momentum, Momentum (p)= mv, velocity final=velocity inital + at

The Attempt at a Solution



V= 20m/s + 9.81m/(s*s)= 29.81
M=(16.0kg)(29.81)
=476.96

Since impulse is the force over time, I thought impulse should be the force needed to keep the hose stationary, but it's not. Any help in where I went wrong would be great! Thanks!
 
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Well, first of all I don't see why you're calculating in gravity. Remember, you're only interested in the force as soon as it exits the fire hose.

So, the momentum would just be the mass discharged per second times the velocity of the discharged mass (16*20)
I took the beginning of physics froma really bad teacher and as such spent my calss time talking to my girlfriend and ignoring the class, so I'm fuzzy but it seems that that should be your answer.
 
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