- #1
JadeBunny
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Rate of change of momentum
Hey everybody this is my first post and I really hope you guys can help me out. Ok so here's the problem which is divided into three parts:
The first part consists of this: A fire hose sends 1464 gallons of water perminutre against a burning building at 92 m/s and does not bounce back. What is the magnitude of the rate of change of momentum of the water. Answer in Newtons.
The second part which I've figured out asks whether the rate of change of momentum of the water cannot be determined, is positive or negative. The answer is that it's going to be negative.
The third part consists of finding the once exerted by the water in 1.7 minutes.
I know thus far that momentum or delta p = mass x velocity
So far I've tried converting the amount of water given into a mass given that the density of water is 1kg/L which gave me a value of 3.786 kg/gal which I used with 1 min= 60 sec to convert the gal/min value into 92.38 kg/sec
I multiplied this by the velocity given (vf-vi= -92) and got a value of -8498.8 N, which when I inputted into the online homework program said was incorrect.
I've been working on this for several hours now and am currently stuck at this moment. The assignment is actually due the 23rd but the answers need to be submitted well before then. Any insight anybody could give me would be greatly appreciated. Thanks!
Homework Statement
Hey everybody this is my first post and I really hope you guys can help me out. Ok so here's the problem which is divided into three parts:
The first part consists of this: A fire hose sends 1464 gallons of water perminutre against a burning building at 92 m/s and does not bounce back. What is the magnitude of the rate of change of momentum of the water. Answer in Newtons.
The second part which I've figured out asks whether the rate of change of momentum of the water cannot be determined, is positive or negative. The answer is that it's going to be negative.
The third part consists of finding the once exerted by the water in 1.7 minutes.
Homework Equations
I know thus far that momentum or delta p = mass x velocity
The Attempt at a Solution
So far I've tried converting the amount of water given into a mass given that the density of water is 1kg/L which gave me a value of 3.786 kg/gal which I used with 1 min= 60 sec to convert the gal/min value into 92.38 kg/sec
I multiplied this by the velocity given (vf-vi= -92) and got a value of -8498.8 N, which when I inputted into the online homework program said was incorrect.
I've been working on this for several hours now and am currently stuck at this moment. The assignment is actually due the 23rd but the answers need to be submitted well before then. Any insight anybody could give me would be greatly appreciated. Thanks!
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