Newton's third law -- Calculate the recoil of a paintball gun

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Homework Help Overview

The discussion revolves around calculating the recoil of a paintball gun using Newton's third law. The problem involves a paintball with a specified mass and velocity, and a paintball gun with a different mass, focusing on the relationship between the two during the firing process.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the need to find the force acting on the paintball and question how to determine the net force without knowing the acceleration initially. There is an exploration of using given values such as velocity and time to calculate acceleration.

Discussion Status

Some participants have provided guidance on calculating acceleration based on the paintball's ejection speed and the time taken. There is an ongoing exploration of the calculations involved, with some participants expressing uncertainty about their results.

Contextual Notes

Participants are working within the constraints of a homework assignment, which may limit the information they can use or the methods they can apply. There is also mention of confusion regarding the calculations and the presentation of the problem.

Baran
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Homework Statement
A paintball with a mass of 0.15 kg is fired from a paintball gun that has a mass of 5.5 kg. The paintball leaves the gun with a velocity of 45 m/s [N] having accelerated for 0.10 s. Calculate the acceleration of the paintball gun.
Relevant Equations
Givens:
Mass of paintball = 0.15 kg
Mass of paintball gun = 5.5 kg
initial velocity of paintball = 45 m/s [N]
time = 0.10 s
I've been stuck on this for sometime now, and am unsure how to approach this question.
 
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Baran said:
Homework Statement:: A paintball with a mass of 0.15 kg is fired from a paintball gun that has a mass of 5.5 kg. The paintball leaves the gun with a velocity of 45 m/s [N] having accelerated for 0.10 s. Calculate the acceleration of the paintball gun.
Relevant Equations:: Givens:
Mass of paintball = 0.15 kg
Mass of paintball gun = 5.5 kg
initial velocity of paintball = 45 m/s [N]
time = 0.10 s

I've been stuck on this for sometime now, and am unsure how to approach this question.
First find the force on the paintball (hint: use Newton's second law).
 
nrqed said:
First find the force on the paintball (hint: use Newton's second law).
I'm confused, in order to find the net force you would need acceleration, wouldn't you?
 
Baran said:
I'm confused, in order to find the net force you would need acceleration, wouldn't you?
Yes, and you can calculate the acceleration. You know the speed of ejection and the time it took to accelerate the paintball.
 
nrqed said:
Yes, and you can calculate the acceleration. You know the speed of ejection and the time it took to accelerate the paintball.
I think I got it:

a= vf-vi/t
a= 0 m/s- 45 m/s [N] / 0.10 s
a= -450 m/s^2 [N]
a= 450m/s

(this is the paintball)
Fnet= ma
Fnet= (0.15 kg) x(450 m/s^2 )
Fnet= 68 N

(this is the paintball gun)
Fnet= ma
a= Fnet/m
a= 68 N / 5.5 kg
a= 12 m/s^2

can you check if I did this right please?
(Sorry about the black lines I don't know how to fix that)
 
looks good!
 
nrqed said:
looks good!
Thanks for all your help!
 
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