Model Rocket Impulse and momentum problem

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Homework Help Overview

The discussion revolves around a model rocket problem involving impulse and momentum. The original poster presents a scenario where a rocket with a specific impulse and mass is launched from rest, seeking to determine its final speed while neglecting gravity and air resistance.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between impulse and momentum, with the original poster attempting to apply the equation p=mv. Questions arise about isolating the variable for velocity and the steps needed to solve for it.

Discussion Status

Participants are actively engaging with the problem, with some offering guidance on manipulating the equation to isolate the velocity. There is a mix of interpretations regarding the calculations, and while some numerical values are mentioned, there is no explicit consensus on the final answer.

Contextual Notes

Some participants question the assumptions made in the problem, such as neglecting air resistance and gravity, and there is a focus on ensuring the mathematical relationships are correctly applied.

bchat112000
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A model rocket is constructed with a motor that can provide a total impulse of 27.5 N · s. The mass of the rocket is 0.173 kg. What is the speed that this rocket achieves when launched from rest? Neglect the effects of gravity and air resistance.



i know that the equation is p=mv (vector based)



0.173*v =27.5N so how do i find velocity...
 
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bchat112000 said:
A model rocket is constructed with a motor that can provide a total impulse of 27.5 N · s. The mass of the rocket is 0.173 kg. What is the speed that this rocket achieves when launched from rest? Neglect the effects of gravity and air resistance.

0.173*v =27.5N so how do i find velocity...
Hi bchat112000. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

0.173 * v[/color] = 27.5 N·s

That's one equation with one unknown. Are you able to isolate that v[/color] pronumeral to one side by itself?
 
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yes by multiplying by both sides?
 
I love this forum by the way, thanks for helping people
 
What is your final answer for velocity?
 
i got 4.75
0.173 times 27.5n
 
ok i plugged the formula ..initial v is 0 final v is 27.5 the mass is 0.173
0+27.5=0.173 This is the formula
27.5Ns/0.173kg=159
 
bchat112000 said:
ok i plugged the formula ..initial v is 0 final v is 27.5 the mass is 0.173
0+27.5=0.173
An equals sign requires what is on one side to equal what is on the other.

This is the formula
27.5Ns/0.173kg=159
That looks better.

Speed requires both a magnitude and units

The correct answer is 159 m/sec
 
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