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Simple Harmonic Motion of a gun

  • #1
(1)It takes a force of 75 N to compress the spring of a toy popgun 0.18 m to "load" a 0.14 kg ball. With what speed will the ball leave the gun?

I used the equation F=kx
I solved for K and I got 416 N/m

Then I used the equation omega = square root(K/M)
I solved for omega and i got 54.5.

Is this correct? It seems wrong to me. Please help, any suggestions will be greatly appreciated.
 
Last edited:

Answers and Replies

  • #2
335
0
Hint: This is not a S.H.M. problem.
f= -k*x
k>> 416 N/m
This is not necessary.
 
  • #3
458
0
The spring energy is converted into kinetic energy. Do you know what the spring energy is now that you know K? Can you figure out the velocity with this?
 
  • #4
Thank you both for your help. I'm still not sure if I completely understand this problem

PE= 1/2kx^2
where I know k because it is 416 N/M and X=.18. so I would solve for the PE.

Then you're saying if the spring energy is converted to kinetic energy, then is KE=PE?
thus KE= 1/2mv^2 and then I would have to solve for v?

But I still don't think this is right because where is the 75N coming in?
 
  • #5
458
0
You used it to find K, did you not?
 
  • #6
Yeah, I'm an idiot. Thanks for your help.
 

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